just thought I'll share this one, I got almost 50 SIM cards after finding out that some providers allow 100% online registration and don't even check if the submitted data is valid. as 2nd phone number I always simply use the one of another anonymous SIM card.
each prepaid card cost 9.75 bucks and has a 10 bucks balance, so I am going Saul Goodman style now....
here's one registration I did, it's better not being TOO obvious I guess (by registering the SIM card on Homer Simpson for example), but I find joy in using data which sounds legit but would be totally annoying to someone who spent money for a subpoena.
b-day month/day = Hitler's birthday
address = the one of an insane asylum
name = "mad scientist" in the horror movie "From Beyond"
enjoy.