Saw a video somewhere on YouTube saying that if yor reseller doesn't remove your MAC from the reseller portal and you go to sign up with a different seller that Mac address won't be available. Is that true? Seems silly that a Mac address on an expired subscription would prevent it from being used on an active one.
I have two subs right now Vader's and Nitro. I submitted a ticket with my reseller asking but I haven't heard anything. I'll probably use different subs for a month before deciding if I want to go back and when I do I'll want a different reseller but don't want to be stuck not being able to use my Mac address.
The video you probably saw was mine.
Some providers purge the system of expired macs periodically some more often then others, but your mac could be locked up for some time unless someone removes it, especially with some xstream codes based providers such as vaders and nitro.
That said, some proiders now let you actually pull from one panel to another. This seems to be the stalker based providers. I know express and some others when they expire, they still show up in the panel but any reseller can activate it and it will swap panels without any intervention at all from your old reseller. It's pretty great.
So in short, it's getting better, and resellers are less likely to lock macs. But that said, it's still wise to choose your resellers wisely.