admitted to the wrong account

[Stoddard]

I've heard of a rare flaw where someone enters their user name and password in their email or Facebook account and is admitted into someone else's account by mistake. Is there any way you can make sure this never happens to you?

[suwunk]

The glitch was a routing problem at AT&T. There is a little known security flaw where the Internet lost track of who was who and the women were put into the wrong accounts.
According to theledger.com reports Michael Coe a spokesman for AT&T said that its wireless customers have landed in the wrong Facebook pages in "a limited number of instances" and that a network problem behind those episodes is being fixed.

source: Routing error puts woman into wrong Facebook account