This is an interesting idea, though with more and more people potentially doing this it is less and less likely to be effective. Additionally, can you point to some sort of confirmation that the duty finder actually prioritizes your own server first? Now that I think about it, it may well be the case given that I've run into people on my server quite often, but is this just an assumption of yours or has SE actually said this is how it worked?

Aside from that, this is certainly not "problem solved". The player base shouldn't have to use workarounds like this (that aren't even guaranteed to work) just to be able to play together. This and the Coil lockouts cause unnecessary tension in FCs when people are inevitably forced to sit out from doing an event and could be easily alleviated if the players stopped just accepting these things and demanding a fix from SE.