Hi Matthew,
please don't get me wrong, I am not saying that we have money to spare. I've not asked for a single penny out of any Fedora budget and yet I've been presenting dotnet-on-Fedora at 4 or more conferences. I always fund myself, from swag to travel and accommodation. The point with those randomly generated numbers I tried to make, is that being more inclusive and having that one valuable contributor there once a year, who is not okay with sharing a room, is worth the 0.18%[1] of the EMEA Ambassodrs budget. Better than having them run away and stop contributing all together.
I would really like to talk about possible solutions though, instead of enforcing room sharing as a rule of thumb. For example Ambassadors could fund only the amount for the shared room, and the remainder could go from the Diversity budget. This type of situation won't happen more than once or twice a year, so I think that there is a solution hiding somewhere.