That's something I hadn't thought of - and I'm glad you've brought it to mind. I'm trying to build a group of riders in and around the Chicago 'Burbs, and that's a piece of advice I need to pass along: When riding in a group, Make sure that if YOU don't have tools with you, someone in your group DOES. Pump, patches and tire levers at the minimum.
I can't say this is that crucial when riding in SF. This group was within 5 blocks of several different places she could have had a quick repair done. It's just fun to hang out with your crew while the glue dries : )