So basically what you're relaying to us is hearsay
One of the guys on the team was trying to add his friend. It wasn't particularly worth it for us to bother with calling ALTA in order to add a line 4 guy so we told him that we couldn't add him but that if he wanted to call ALTA and deal with the red tape he was more than welcome. ALTA didn't put it in writing or anything else like that- they simply told him that this was the rule and he was free to play on an A level team. I have no reason not to believe him and I think that their rule makes perfect sense within the goals of their organization. Someday when you are actually on a tennis team you will have a better idea of how things actually work.
I know the rules inside and out and this is one that I haven't heard of before- I simply thought that other people here would appreciate knowing about it as well.