Yeah, getting "inked" from monster source is a positive thing, but you have to get sprayed a lot of times for it to have a great effect on your scent (currently, 1 intensity/-50 scent is generated by every 300 duration). Also to get "inked" by monster in first place, monster has to be aggressive to you.  I don't really see much room for abuse, but I could slap on some morale penalty. 