I remember when AOL kept trying to lock 3rd-party clients out of their Oscar protocol (for AOL IM). They resorted to requesting random chunks of the official AO

I remember when AOL kept trying to lock 3rd-party clients out of their Oscar protocol (for AOL IM). They resorted to requesting random chunks of the official AOL IM binary to verify that it was an official client. To keep up with this, 3rd party clients would have to distribute AOL's client with theirs, and then AOL could sue them for unauthorized distribution.