I have never lost one to a fish...I think once I lost one to the bottom though. (Have trolled them since the day they were invented) Draggin umbrella's with wireline is not my favorite way to fish....but I *always* keep a pair of rods on board rigged for them because some days thats your only choice. No one can argue they are not effective.
I have seen some "home-grown" rigs that have hooks on every tube on an umbrella rig. Trolling that thru a school of feeding bluefish could get you upwards of a doz or so fish on a single rig. I think you could break it off that way.
Most guys used 60# test wire with 80# mono backing which rarely breaks. I suppose if it did break the rig would sink and the fish would probably die (a few may ge the hook dislodged and get free).
These things just don't fall off like casting plugs do, I would not fret about it too much.
Don't forget, the fish would die if you keep them too.
