Allowing only certain arguments in launchfile

edit

No, this is not supported in ROS 1 (or at least, not in the default roslaunch, there could be community contributed extensions which may add this, but I'm not aware of them).

I find it problematic if a user doesn't get notified in any way if he e.g. mistypes or runs into version confusions or something like that.

Yes, that could be problematic.

Current best-practice in ROS 1 would suggest to make sure nodes implement parameter verification and to make them very vocal about things not being as they should.

And don't set defaults on args, nor use default values in nodes if at all possible (to prevent "silent" misconfiguration).