I have my GPS wired so that it can be turned on independent of the key being on, but it is not hardwired to the battery. I have an unswitched power strip installed that goes to the battery through a fuse. I sometimes do some extensive searching or navigation when the engine is off because I don't want to have the key on the whole time so the unswitched power works for me.
A couple of times I have come into the garage the following after noon and found my GPS still on
While this has pissed off my battery, my bike still started ok. Disclaimer: My GPS is a down grade Streetpilot 2730.