The guidelines I personally use are to apply if my qualifications match 75 to 80 percent of the key required qualifications, and I know I can quickly pick up the other 20 percent. Those who are randomly applying are really making it harder for those of us who are selectively applying.
HR departments are so flooded that they're now hiring companies to screen the resumes and using poorly built Applicant Tracking Systems. The problem now is that since these outsource companies don't have direct contact with the hiring manager, they really have no clue as to what constitutes transferable skills versus an exact match and the ATS's can't discern alternate terms for the same keyword.
I hope with this post that you're trying to bring attention to this and hopefully some people will get it. They're only wasting their time by applying to jobs they're in no way qualified for and making it harder for hiring managers and HR departments to fill these open positions.