Choosing the round isn't manual when there's multiple, it's done automatically based on the round parameters.
Does that mean there are default round parameters hardcoded in the client?
If a coordinator is running many rounds in parallel with low minimum input counts/fast input registration timeouts, you should already be avoiding them altogether since their config isn't making good use of scarce block space.
Theoretically, it would might be recommended to avoid them, but practically, there is no internal function within the client that would let me know they're running rounds in parallel, AFAIU. That's something I need to manually check. For example, I need to notice that my coins belong to different coinjoins. Isn't that correct?