Do employers actually know or care about lying on resume?
The current system of job seeking often requires to lie on resume. It is even being highly recommended by people that coach people for job seeking, although with some moderation of course.
Do not lie on your resume. Especially if you are a software engineer! When I give interviews, I typically don’t ask random technical questions. They are catered to what’s on your resume and if you can’t explain it, that’s a huge red flag
I think OP may need to explain further. There's embellishing your work history, or tailoring it to a particular position you're after. That's fine and part of the CV-fu. Then there's outright lying about hard facts, which can be a huge problem if checked.
Hard facts are things like who you worked for and when and on what position, or where you got your degree and what it says on it. Provable skills and certifications also fall under this category.
Same. I have a list of questions on various topics, I'll ask a basic one about most technologies listed on a resume, and follow up if the answer is good until I reach a question they can't answer, or I'm satisfied that they know the subject matter well.