[straight_talk_2]

No, it's not required. Try the link in a private mode tab or different browser.

This is one of those evil tricks, if Microsoft or Google know somehow you have an account they'll try to force a sign in ever after.

[packetslave]

"evil trick" is pushing it, a bit. If I had to guess, the algorithm is more likely something like "you have a Google auth token in your cookies but it's too old, so you need to log in again"