In reading up on this, I’ve learned that a small minority of backcountry BWCA folks carry FRS/GMRS - mostly those like me with larger or multiple groups. Beyond that, people carry either nothing or a Personal Location Beacon like an InReach or ResQLink. We’ll just be doing day trips, I’ll go the IP67 5W GMRS route (UV9G, RB23, S88G, etc). Apparently, there aren’t really people up there using Marine VHF. So nobody will hear you.