SingIn - session[PUT] - shouldn't it be [POST]?

[hepiyellow]

According to this:
http://restcookbook.com/HTTP%20Methods/patch/
"Also, the PUT method is idempotent. PUTting the same data multiple times to the same resource, should not result in different resources, while POSTing to the same resource can result in the creation of multiple resources."

Since the response of this request would have the Created resource (the session), which includes a sessionId. and I think multiple requests would end up with different sessionIds. So using PUT is wrong, and it should be a POST.