Good on you for having the meta-cognition to recognize it.
I've graded many exams in my university days (and set some myself), and it's exceedingly obvious that that's what many students are doing. I do wonder though how often they manage to fly under the radar. I'm sure it happens, as you described.
(This is also the reason why I strongly believe that in exams where students write free-form answers, points should be subtracted for incorrect statements even if a correct solution is somewhere in the word salad.)
I've graded many exams in my university days (and set some myself), and it's exceedingly obvious that that's what many students are doing. I do wonder though how often they manage to fly under the radar. I'm sure it happens, as you described.
(This is also the reason why I strongly believe that in exams where students write free-form answers, points should be subtracted for incorrect statements even if a correct solution is somewhere in the word salad.)