The deconstructing problem IMO is not so much of a problem. It's easy enough to impose restrictions on what a person can and can't do when they aren't trusted.
What about the destructing problem? (i.e. nading/painsawing/lucifying/flaming/etc. the base) That's something harder to deal with.
You can just turn freindly-fire off for structures. This would mean no penalty for lucifying anything that comes near the base or whatever else that would result in losing half of your buildings and earning a dunce cap. This, like most FF can detract from the realism. (IMO dretch FF is the only good one, as I prefer to think of dretches as tough like rubber).
