This^^^^. I've seen it happen way too many times to be coincidence; you look at something a few times, the browser cookies left on your system by the website during your previous visits trigger an algorithm on the server to pressure you into perhaps making an impulse buy because you fear "losing out".
Being in someone's cart for days on end means nothing. Any item is available until it's actually sold and money has been exchanged. I never put anything in my cart unless I'm going to actually buy it.
