Scheduler is really designed for booking appointments with teachers (not rooms), hence the conflict checks.
If you would like to change this in your installation, then i think that editing the function scheduler_instance->get_conflicts(), so that it always returns an empty array, should do the trick. (This is in mod/scheduler/model/scheduler_instance.php .)
I'm not sure whether this makes sense as a built-in option though. It would be quite easy to include a global option (conflict detection yes or no, for all schedulers), but is this what users want? If this is supposed to be an option on a per-scheduler basis, it becomes more tricky to implement I guess.