I found it when I clicked Diet's link in OP, it takes you to a log in page, that asks you for your email, and in-game password, then you're taken

to the shop-page, at the bottom of which, it gives two options 'agree/disagree', as well as clickable explanations for: 'personal info', and 'privacy policy'.

When I accessed crown buying while I was in game, none of this came up.

I opted to not buy more crowns this time, but I guess they still have my info now, and even if they honor what they say; the 'decline' wouldn't be effective until I click the disagree button, any info they saw before that, would still be in their records.

One final thing, Diet's link stays on Google, and you're not actually in game, when you 'sign in';

whereas, if you go to buy crowns while in the game world, an IE page comes up.

Hope this helps.