Barrel plug will do it too. It's an odd behavior, for sure.
I don't think I even realized it had a suspend sensor in the lid. I suspend mine via the power menu, wait for the green LED to go off, then close it. If you've got the proper suspend (deep sleep) stack working, it's very much a power sipper when asleep as well - I've had it asleep for a week (when I thought it was off), and still had plenty of battery when I woke it up.
I don't think I even realized it had a suspend sensor in the lid. I suspend mine via the power menu, wait for the green LED to go off, then close it. If you've got the proper suspend (deep sleep) stack working, it's very much a power sipper when asleep as well - I've had it asleep for a week (when I thought it was off), and still had plenty of battery when I woke it up.