To what extent were the SIFT patents enforced? As an undergraduate I worked as an RA for some (IEEE published) research at my uni for some robotics work and I gather that violating the SIFT patent was somewhat common when it wasn't obvious SIFT was being used, e.g. when SIFT was being used as a fungible solution: Self-driving car demo that recognizes road-signs? No, that's too obvious. Object recognition primarily us…
Keep in mind that software patents are only enforceable in the US and Japan. Everywhere else in the world, you can do whatever you want (only copyright applies). For businesses, it's still a big deal most of the time because you usually can't really neglect the US market, but for academia, there is no such issues.
That is sadly untrue. There is a lot of confusion on this front because "software patents" are a specialized term of art that essentially means 'a patent that describes a procedure with no reference to a machine'. There was a period of time in the US when such patents were enforceable, but more recent cases have mostly changed that (Basically Diamond v Diehr in 1981 to CLS v Alice in 2014).
But all this is moot, because patents that apply to the software-implemented functionality of machines are common even without "software patents". I've followed more patents on software cases in _germany_ than anywhere else.
You're absolutely right about businesses. The US alone would be enough of a problem, but it isn't even the US alone that is an issue here.