I have Avast running on my Mac. When I logged into its control panel just now, it asked me to register this device. I logged into my account, and sure enough, it’s now showing two listings, with the same name. I don’t know that it’s a big deal, but it’s at least mildly annoying. I can’t find any obvious way to merge these or delete the obsolete entry.
I’m concerned that if I ever want to register for anything beyond the free version, this could be a problem – if it decides this is a new device again, it might think that only the “old” device is registered. :-/