Authenticating a valid EQ license

[WildcardX]

I hope asking this doesn't get me into trouble. This is not a request for warez.

I gather the reason EQEmu doesn't patch clients to a version compatible to the server is because there is no way to determine what is a valid EQ client license and what is not, but I am curious... Assuming there was a way to determine what is a valid key, would it be a violation of the EULA to then patch a client?

For example, suppose I am running a server and my neighboor, Chad, wants to play on my server, but he already patched to live, which is a version of the client that will not work with my server. Chad comes to me and brings me his legally purchased Sony Everquest CD's and shows me his key. Once I see this key and he establishes he has in fact purchased and owns a legal copy of the client, would it still be a violation to patch his client then?

NOTE: this is a hypothetical question only, it is not a request for warez.