A little while ago, there was an outage which was ultimately caused by a few accounts abusing the system with unreasonably many searches and those (rightfully) had their accounts terminated. So yes, they do look for that.

I highly doubt they’d get suspicious on a small scale or even have any monitoring set up for that. People have all kinds of circumstances, so access from different IP addresses isn’t necessarily multiple users either.

It’s like theft at a grocery store. A poor person stealing a little food for themselves won’t affect their bottom line very much but organised criminal groups targetting high-value items will destroy it.