If flying under bridges is so dangerous, we should have a count of the number of airplanes that hit a bridge, adjacent terrain, vessels, vehicles or persons underneath.

Since it is done so rarely the stats are invalid.

It may be safe to fly under a bridge - but only if there is a ground person to radio that:
No cables or ropes hanging down, no bungee jumping taking place, no vessels about to pass under the bridge, etc.etc..

And boats do it daily

A short survey of youtube shows how many boats strike bridges! I'm anazed there are any bridges left...

TOO

If she wanted to fly under the bridge as a middle finger to the authorities / retirement stunt, she should have done so and then faced the consequences head-on. Trying to weasel out of it with various ADS-B related excuses is, in my view, pathetic.