Not all open source devs are from the USA and in a lot of place outside it say the EU it can be quite the hassle. If you do it wrong it can very well be more than 5k worth of effort to fix it. When the taxman comes out 2 years later with a fine saying you didn't do X or Y.
In those countries the taxman will come out anyway because it will say that it was not a donation and you are trying to avoid paying taxes. It would be better to speak with an accountant beforehand in either case
it not about avoiding paying them (you will anyway unless you're in very narrow class of orgs) its about being in the wrong legal structure and getting stuck in administrative hell because you don't fit in their tidy little classification boxes.
