I've requested rollaway beds many times from each category, in the US, Europe, and Asia. I've never once actually been charged. Most recently, at the Westin Singapore, when I called to housekeeping upon arriving in our room to have them bring it up, they even reminded me that there would be a SG$100 per night charge... and yet, no charge upon checkout.

Of course, YMMV. I'm sure plenty of others can probably attest differently.