Roughly roughly and out of my mind... 250€ as safe average for EU, 800€ as safe average for US and around 1000€ as safe average for rest of the world.

Any help fine tuning these values with current prices and cases is welcome.

Going through travel agent is the way to go in any case, as discussed months ago. I'll call the one that worked with Mozilla/Maemo in the Danish weekend. Their commission was fair and they took a lot of lego work booking flights and dealing with small payments. They do Ryanair style flights as well.

We can deal with exceptions for reimbursement, but we can't make it the norm.