Preview Gmail's new look?

Very much like how Google offers you to download Google Chrome even when you visit the Chrome homepage, as I ranted about a couple of weeks back, Google asks you to Preview Gmail's new look even if you already have that as your style.

I had went into the Themes and changed it much before Gmail had started prompting me to try their new look. Though I know Google will not keep a flag to maintain if I've tried the new look or not, and accordingly show me the preview link (that anyway takes to me a page titled What's new in Gmail?), I tried from another account I maintain where I had not changed the theme, and I get the preview offering even then.

Changing the theme may be just changing a css file, but that info should exist in some column in their databases against my user id. Can that not me used to not show me an option that I have already availed?

When Google knows who do I talk to, where am I planning to go for a vacation, what do I like to eat on a Sunday afternoon, which IPL team do I support, does it not know what browser do I use to access their products, or what settings I have in their products?