I usually give a thumbs up, only stopped a couple of time when I didn't get a response ....... or got thumbs down. One I ended up pillioning him home as he needed to get to his kids parents evening, the other a quick chat and I was on my way ......... Alot goes on the look of the person for me, both were on vintage / classic machines ....... I don't know anything that could help mend the machines but the chances are there's no-one stood behind a bush with a knife I've been stranded on the side of the road before waiting for a knight in a white van to arrive and would have welcomed someone to stop and keep me company lol