Originally Posted by WillCAD

I suspect (assuming the OPs flights passed through US TSA jurisdiction) it was removed by TSA for inspection and not replaced afterward.

If it was TSA approved, it was probably just forgotten. If it was not TSA approved, or if the symbol wasn't obvious, the TSO may have cut the strap off. Either way, there should have been an inspection notice inside the bag when it arrived at its destination.

If the bags didn't pass through TSA jurisdiction, all bets are off.



I know my travels are a small sample size, but I've been using an external strap on my checked bag for about twenty years and never had an issue with the baggage handling equipment. Like OP, mine is one with a TSA lock on the buckle, and I thread it through the bag's side handle and tighten it like a compression strap so there is no way to get anything caught under it.

It's my understanding that baggage handling equipment at US airports is basically conveyor belts with side walls to guide bags through the system. Bags can get stuck, I know that, but I don't believe there are any protrusions inside the system that could get caught on a strap.

After all, if something could get caught under a tightened strap, it could also get caught on a protruding handle.

Now, DANGLING strap ends, that's a different story. You don't want any dangling straps on a checked bag, those could get caught between rollers and under the belts and cause all sorts of backups in the system. I've been told that by airline counter staff a couple of times over the years.