I've just found this thread while trying to investigate a saved password in Tweetdeck ... it's all working fine (my problem is that I can't remember it, so can't enter it into another installation of Tweetdeck - and the "I've forgotten my password" doesn't seem to want to email me the p/w ... yet trying to set up an account with the same email address tells me [unsurprisingly!] that I can't have that email address as it's already taken!)
So, as it's all working fine - do I need to remove it? Won't it just re-create one when it needs it, or will it store it in some other bit of the Keychain??