Interesting question and certainly something to think about. A running group that I run with just recently did the same thing - The person that co-ordinates when and where we run just said that everyone who shows up for a run will have to sign a liability waiver to have on file for the group runs. I’m not sure if there was something that happened that sparked this all of a sudden but suspect there might have been.
It certainly wouldn’t hurt you and could definitely protect you so I would think you might want to consider it.