Thankfully, my current employer doesn't have this policy (and I think I might refuse to travel if they did).

At one of my past jobs, there was a corporate retreat where we were all assigned to share rooms with someone of another office for "bonding" purposes. I lucked out, got along great with my roommate and all was well. A friend of mine wasn't so lucky -- he begged to stay in other peoples' rooms after the first night because his roomie evidently cried in his sleep and it freaked him out. I think that's one of those instances where the "bonding" idea can really backfire -- no one looked at the crier in quite the same way again!