Obviously you're joking but seriously, why would anyone even think of having to disable imessage before removing their phone number from the device? It just doesn't make sense. I sure didn't think of turning it off. Why would I need to?
Then I searched online and realized this was the problem with my messages and had to put my sim card back in, turn it off, then take it back out. Imagine being a Verizon customer, now that's a major hassle.