Most of the time, if I see a lone rider or even 2 riders stopped and trying to fix, I will come to a full stop and then ask them if they need assistance. The mere action of stopping says a lot and really gets the attention of all parties. The likelihood of a meaningful conversation begins. Sometimes they have a small minipump and I show them the Topeak Road Morph and how much easier it would be for me to get it past 100 psi. Then they quickly change their minds and let me help them.

That's why I don't carry CO2 cartridges and use a lumbar bag for more emergency stuff.