Personally, even after using the "Can I transfer my number" checker with the new carrier and verifying my number can be transfered, Verizon refused to transfer my number when the time came.
Something about local contracts between carriers that can only be checked when attempting the number transfer.
Yeah suspected I was being lied to and probably should have fought harder and should have done a lot more preemptively. I really shouldn't have made purchasing choices based on the "Can I transfer" website thing, that's my bad. I even had my new carrier conference call Verizon with me to try to have the number transfered. According to the agents they had "never seen this problem", I wish I had the call records or that this was done in writing/email, sigh another mistake. Lol