I also don't really see the point. Insurance is for risks that will wipe you out. Insuring things for levels you (and therefore likely your friends) can afford is basically just a stochastic wealth transfer to whoever is better at estimating risks.

I also couldn't think of anything more embarrassing than using a friend this way. Could you imagine having a conversation along the lines of "hey can I use you as an insurance company, if I'll pay you $10 will you pay me $100 back if I'm Ill for a meeting?". Frankly I've never heard anything quite so ridiculous.

And it's not like it's hard to get travel or event insurance from actual providers. You can even get multi-trip monthly or yearly travel insurance.