But again, if a hacker can know what website you have opened at any given moment, you probably have other security problems to be worried about.
How many public places offer free wifi and how many people use it? A hacker could be close enough to visually spy and know what page you are on, and close enough to take control, and you'd be more likely to want to use one of those cheap compact mini wireless mice than lugging a big wired one around with you.
Time is always a factor. It looks to me like people expect immediate breaches of their security, because a hacker swoops in, breaks security and robs you blind of information and/or money. But in my (arguably rotten) mind the most successful hacker is the one who has a bit of patience and gets to "know" the target by studying any type of data he/she can get from his/her target. That mouse data would sure help in case social engineering isn't an option.
You mean like studying the guy who uses Starbucks as his office, taking advantage of their free wifi and easy access to coffee, and works from there, predictably, every single day? He sits at the same table each day, sets up his laptop, wireless mouse, etc. and stays there for about 4-6 hours, Monday through Friday.
If you know this and can show up before he does, you can choose a table close enough, that gives you a fairly clear view of his screen. You can pretend to be someone just like him, working from the same coffee shop every day, just like him, strike up a conversation, get to know him, all while spying on him as he works.
Might not be worth the trouble in some rinky dink town to try to target an individual like that, but in a large urban area like NYC, Seattle, or San Francisco, it could be.