[pc86]

It's not his duty to do anything, and he's explicitly saying people have accepted speaking slots then not shown up so your doubts are unfounded. Have you never attended a conference where there is a last-minute change in a speaker or talk? Theirs is not the first time I've heard of that happening, either.

[throwaway290]

Have you never attended a conference where a speaker was not from a developing country but didn't bother to show up anyway? I had

I say charge more, take higher deposits if needed but be more hands on with all speakers (not discriminating against "global south"): get their precise arrival info, always be in touch about their status, meet at the airport, organize their accommodation, etc. So they have no chance to escape your hospitality

[ghaff]

A large tech conference may have 100+ speakers. They're not all getting the white glove treatment.

Life does happen in any case--especially in these days when people are acutely aware that they can't show up at conferences with an illness. I've also filled in for a speaker who just totally forgot they had a session at the conference and were double-booked elsewhere. It happens. Might seem odd but it can happen when you might have a a dozen speaking slots a year and many more proposals in flight.