Yes, that can absolutely happen. In fact, that exact situation is happening right now with !gaming and !gaming
Not really an issue if you subscribe to both though.
In the longer term, I fully expect duplicate communities like that to resolve themselves with people predominantly using one over the other. EDIT: Or another possibility is that they might end up different due to moderation and rules (i.e: one is the memey gaming community and the other is the more serious one)