An excellent point there.
I found a "Bird Nest" of mono tightly wound behind my trolling motor prop a while back, no issues, I was just looking one day. I was really surprised. Now at least once a year I check behind my Mercury prop and the trolling prop.
Glad you posted again about your lithium/trolling issue. I guess you can run it safely at 80% and all's well. Consider it like a speed limit, and you don't need a speeding ticket!