I ride Critical Mass in my city and even when we have a large group we ride in groups of two, side by side - in one lane. We use hand signals. Shout our intent too, if the group is large enough. I'm in my 30's - and so are alot of my regular Crit. Mass buddies. Most cars are annoyed no matter how well we follow traffic rules - and honk - flip the bird - or shout other offensive things. It's frustrating, but we never respond. Act normal, and try to maintain formation. We do our best.
"Things look different from the seat of a bike carrying a sleeping bag with a cold beer tucked inside." ~Jim Malusa
2009 Trek 520-Brooks B-17 Special in Antique Brown
2010 Surly Long Haul Trucker-Brooks B-17 Standard in Black
1983 Fuji Espree Single Speed-Brooks B17 British Racing Green