People sometimes sign waivers at rallies, but only if they are sponsored rides. I have never signed a waiver when it is a bunch of us just going for a ride, even when it's been planned for a while.

There are a bunch of us at work that are planning a long ride at the end of the month. But, it is just a bunch of us just going for a ride, not sponsored or endorsed by work or anyone, so no waivers or anything.

Soren