I've never been busted in New England. I usually stop the bike or get off when I encounter hikers. Since wilderness is nearly always tree covered in New England, I don't think they'll find you with helicopters. Unless you're doing the Presi Traverse or something high in the Whites. Still, you should use a little bit of the common. No large groups, races or events. Not the most popular trails on the big days. Pull the bike rack off your car and throw it inside etc.