Enforcing "Destination Theme" when pasting slides

Working on PowerPoint-Slides in a Team: is there a way to force users when pasting slides from other presentations to always use the destination theme? E.g. disallowing keep source formatting?

We have sometimes more then 20+ people working on a slide deck - not everyone sticks to the rules. So, it would be the best to enforce a couple of things:

- that only the destination them can be used when inserting slides from another deck

- that the default (!) of a text box is 12 Arial left and the box no autofitting / this defaults (!) should not be changeable .... but the formatting can be changed if the user needs to.

Thanks in Advance for any hint