@User: It would be a hard DRC error. That doesn't mean that you shouldn't do it---experimentation is encouraged---but we would have to run it by the SkyWater engineers.

Would a design with DRC errors caused by experimental geometries be accepted for fabrication in the MPW?

Depends on the situation. When the process engineers fear that it might blow up (e.g. antenna rules) then they wont accept it. So if you can proove that even if your experimental geometry fails that it still cannot blow up, you likely have better chances of getting it accepted.