Paypal payment without authorisation

[CalamityJaneToo]

On any transaction, with the exception of eBay, using PayPal I am directed to a PayPal login page to complete payment. I have just used Wayfair for a purchase and chose PayPal as the payment method BUT it did not give me the PayPal login page. It completed the transaction as if it had the password. Wayfair confirmed they do not store PayPal passwords and blamed it on my browser cookies, etc. My browser is DuckDuckGo which does not, as some may know, store any information. Has anyone any idea what is going on?

[Ouch]

I've just experienced this. But I'm thinking that it happens only if I have made an earlier purchase via paypal on the same day (or perhaps within a few hours). That is, it appears paypal stores a cookie on my PC that tells it that as I've already given it a password and authorisation code earlier the same day, it kindly does not ask for this information again. It's a bit alarming though, giving one the impression that a retailer I'd never used before somehow could extract a payment from paypal without my giving him any password. It also seems to mean that if the PC were in some public place and I just left it, anyone else could come along and make purchases via my paypal account without any check.