They would if I meant "not logged in by default" on the same browser, but I mean on completely separate devices which have never even touched my Twitter account—not out of paranoid sandboxing on my part, mind you, just no motivation to log in. I barely tweet anything at all, so why bother login in.

Could they still know it's my "user" who is seeing this or that tweet, by using intelligence-agency level analysis on usage, personal connections, and networking patterns to determine that it's me? I'm sure they could. But why bother to such a massive level of complexity when they could simply require login to view tweets instead?

Have you been introduced you to Firefox containers? Best feature the masses will never use.