Think I Found A Security Bug [GMail]

backstory:

i have two iTunes accounts. one for the german store and another one for the US store. I have been using my e-Mail: "x.y@googlemail.com" for years (Google wasnt allowed to communicate it as gmail in Germany cuz the word was patented by another firm or sth so i never set it up as gmail but both ways work) on the german store.

ANYWAY ... i have decided to change my hotmail email on the US account and for the fun of it i tried "x.y@gmail.com" and it it worked! their system doesnt seem to recognize that it is actually the same e-mail address. as far as i know you cannot actually use the same email for different apple ids, right?

so basically someone could set up an Apple ID with "googlemail.com" instead of "gmail.com" and i would see what the person has downloaded etc? cuz i would get it sent to gmail