When acting as the Chief Pilot in a nearby country, I couldn't get over the number of hours In-Command logged by some Kiwi Twin Otter copilots when checking their logbooks to confirm they weren't busting the max/p.a. That was the way they logged at home, so they freely logged Copilot time as Command so they could get the time up towards the ATPL requirement for an upgrade to the left seat. All without any input from the Captain of the day. If they did the alternate sector, they logged Command.
I would not sign or stamp their logbooks without confirmation from the Captain that on that sector they had complied to the standard definition of Command ICUS ! Must have upset a few, as I wasn't kept in the position for long....