Judges get booster boxes, judge foils and even money as compensation for judging events.

How do we and the tournament organizers deal with taxes that arise from this? I am not asking for a lawyer's advice, I'm curious if someone knows what, for example, Grand Prix organizers, consider this expense in legal terms.

Each organizer will do their best to comply with tax laws in effect in the jurisdictions where they do business. I'm sure that many of them have already consulted with tax attorneys and/or accountants.

And I'm afraid that's all we can offer you, in this forum: please ask your own tax expert. No one in this forum is in a position to provide you with tax advice.

As for what some organizers consider this expense: you may be asked to supply some sort of tax information - in the USA, perhaps a W-9 or W-8 - before you can receive compensation from certain organizers. That's a fairly good sign that you should probably consider that as reportable income - but again, you have to seek expert guidance on that (or sort out the tax codes yourself, if you feel brave).

I'm sorry to squelch discussion on this topic, but this forum is not an appropriate place to seek or provide legal advice.