If you see something...

Once again shots have been fired.

Once again the lives of innocents have been lost.

Once again America mourns in the wake of a brutal massacre.

And, once again, the slaughter could have been averted. But nobody had the guts to take proactive measures.

Parkland is a community about 10 miles northeast of Pompano Beach, Florida and just north of Coral Springs. It is bordered on the west by the Everglades and looks east to a treasure trove of golf course communities.

Two of the closest are the very upscale Parkland Golf and Country Club and Heron Bay, once the site of the PGA Tour’s Honda Classic.

But, like many locations in Florida, all of the opulence often is located close to the far opposite side of the economy. The trailer park, home to America’s latest mass murderer, is one of those sites. In it lived a tormented example of pure evil – one who provided portents of his revenge on society for many years.

In the wake of last week’s massacre at Marjory Stoneman Douglas High School, Florida Attorney General Pam Bondi issued an oft-heard plea: “The most important thing is to be alert and report suspicious activity. No threat should be ignored.”

The War on Terrorism also encourages, “When you see something, say something.”

But why is it, after another attack has taken place, we hear so many tales of early warning signs. Social media posts showing an obsession with guns, reports of irrational behavior, hate speech, threats. Yet, still, the disaster is not averted.

Are these grim instances the result of people ignoring the signs … or officials failing to act when troubling details are reported?

Those questions will be asked over and over again … throughout the investigation taking place in Parkland, Florida. But will we ever have any answers? Could tragedies like this … or the one outside the casino in Las Vegas … or the one in the Colorado movie theater … be averted?

Should we have been protected from terrorist activity, like the infamous 9/11 attacks or the Christmas party shootings in San Bernadino?

In each of those cases there were warning signs.

Fast forward to a Southwest Airlines flight from Orlando to Philadelphia last month.

There was reason for concern when a couple, probably in their 30s, and a young girl, probably around 12 or 13, arrived together at the gate. Obviously, they were traveling together. Presumably, they were a family.

But the woman -- neatly attired in workout pants, Tshirt and sporting long, blonde braided pigtailed hair – immediately drew attention to herself. Her navy T-shirt had block lettering on the front that read: “I am having a great [expletive] day.”

Except there were no missing letters in the vulgar message. It was clear for all to read.

She seemed to be a bit hyper, but nothing compared to her male traveling companion. An amazingly fit – maybe too fit – specimen, he appeared to be in an agitated state. He seemed poised to strike, his eyes darting back and forth. The young girl was oblivious to anything … head buried in her smart phone.

Most people seemed to be trying to ignore the scene, fearful of being dragged into something after staring too long at the spectacle.

My first reaction was that the woman would be denied boarding access. No such luck.

Instead she entered the plane and chose one of the few remaining seats in the front, a

middle seat in the second row. Her companions continued toward the back, until they found two seats together.

She hastily tried to negotiate with the other passengers seated in the second row for those seats, saying she wanted to sit with her family. She was denied by both, one of them being an elderly woman who would not have been able to walk to the back of the plane without assistance.

She then left the second row and went to the back to report the negotiations failure. Finding another seat near her companions, she sat for moment, then clumsily started making her way back to the front of the plane – against the flow of boarding passengers -- to retrieve her backpack.

At this time, I reported all I had seen to the flight attendant. I asked if she had seen the T-shirt and mentioned I was surprised she had been allowed to board.

The flight attendant sloughed it off, making some comment about free speech. When informed of the agitated behavior of the male companion, the reaction again was somewhat dismissive.

The side show finally got seated, a couple of rows behind my spot on the plane. A young man next to me also noted the strange couple and commented. We decided to take turns keeping an eye on the male passenger, who sat rigidly at attention, throughout the flight.

Thankfully, nothing happened – except experiencing two hours of high anxiety aboard the airplane.

Unfortunately, that was not the case in Parkland, Florida. The blood of those 17 high school students is on the hands of a lot of people. There were those who repeatedly saw the signs, yet did nothing. There were healthcare and law enforcement officials who responded to abnormal activity and didn’t go far enough.

Now, Attorney General Bondi’s warning continues to ring in my ears, “No threat should be ignored.”

The burden of reporting suspicious activity is falling on all of us. But what happens after that?

In too many cases the answer is … nothing.