A modern BFS reel with an ultralight spool can certainly be damaged by too much pull, especially when the line is coming of the side edge of the spool. Many of the very light spools are supported only by one disc of aluminum in the center, not by both ends as in a normal spool. Hence, they are susceptible to bending. Having a drag that maxes out at low poundage and using low pound-test line prevents this from happening. Some braids rated at single-digit pound tests actually have much higher breaking strength.
I have never (yet) been spooled on a bait caster; even a BFS model with a very shallow spool and very low line capacity. I can see where it could be a possibility with a big fish hooked at the end of a long cast, but as I said, I think it's slim odds. I have been spooled on a fly reel though, and it's a bad feeling when you get to the end.
My favorite lake, Lake Champlain on the NY/VT border, is home to some pretty monstrous northerns! They are a lot of fun but on a good weekend of bass fishing, they might cost you some money in lost lures. I usually land them on the heavier bass gear and thicker leaders, but the darn small ones and pickerel that hit the BFS stuff with light line and leaders usually swim off with the lure. It seems like their teeth always cut the line just as you're about to reach for them or net them!