Usually forget or take to room once a trip when in a hurry Never charged but do always tip and always try to return.
Forgot ours on the Boobs Cruise...they're in Steve and Jannet's bathroom now LOL. They do not track the towels.
We take ours to our room every day and return it in the morning. We use it for the ice rinks they call floors when we shower up for dinner and Bash. Never had an issue.
