I know the organizers caution against riding in a close group, but I'm sure it's going to happen at some point with some people....I was out last night for a ride on the Martin Goodman Trail, and a guy I passed took the opportunity to jump on my wheel (uninvited). I'll save the diatribe about the level of politeness this entails for another time.
However, when I got to my turnaround point, I signalled that I was slowing and turning, and we had a very near miss. I take part responsibility for it, as I often ride with a club, and our hand signal for slowing or stopping is a hand (open palm, or fist) on your lower back/upper butt, not the arm out and down shown in the traffic manual.
Other signals you may see are an arm out to the right for a right turn (rather than left hand pointing up at a UFO or something)...Pointing at the ground (either hand) means watch out for a hazard...A sweep of your left hand from front to back means pass me or take a pull (i.e. your turn in front)...
Know what you mean about following too close. Had a group out riding following me (I still can't figure out why, I'm not exactly fast) and when they went around me (without telling me that they were going to do that), one clipped the back wheel of the bike trailer and flipped it, with me lying on the grass wondering what the h e double hockey sticks just happened. Thankfully, my son wasn't hurt. Then the person that clipped me (who evidently went flying) tried to blame me for it. The nerve of some people, I tell you.
Sorry...that should have been back to front, like being waved forward. But you get the idea...
TBA, glad to hear you're ok, and your son too...I had someone riding my wheel last year (unknown to me at all - it was dusk and I was looking ahead) go down when I put my brakes on. I stopped ok, but she was shaken up after sliding on the pavement...I did stop to check on her, and no other damage.
The moral(s) of all these stories...
a) Don't jump on without the leader's knowledge (and if it's a stranger, asking is just plain courtesy - I don't mind pulling, but if you don't ask, that's rude). If I don't know you're right behind me, I'm not thinking of your safety, comfort, or anything else, and I'm going to be VERY unhappy if something untoward happens.
b) Know hand signals. Sometimes they'll be a little different than what you may expect. Adapt.
c) Be courteous! Stop if someone goes down. Take a pull. Let the person in front know you're there. Say thank you (a wave or nod as you pass will do).