if there is a ratings min or max, players outside of this range are automatically booted at the start of the match.
Registered players disappear from Team Match when challenge accepted?

No, this is not like that. Most recently, the player booted was rated 1516 in a match where the upper limit was 1600. Previously (last Fall) a different player rated in the 1900s was dropped from an unlimited match. In both cases, we had to have more than 15 players per team and we were well over that.
I believe I have seen this happen twice in World League play. Has anyone heard or seen this occur? I did not find it as a previously reported problem. Thanks