I'm sure adcoms have seen most everything, and can probably detect liars. Also, you'll have to speak about most of your ECs in your interview, and I bet they can detect BS. That being said, it's mostly on the honor system - maybe, in theory, you could get in with a fraudulent application with fake ECs and contact numbers. But if it ever came up that you lied....well, good luck😱
If you actually did the hours, you shouldn't worry. The committee probably won't call the doctor, and if they do - they probably won't really scrutinize over hours (unless you say you were shadowing like 30 hrs/wk when in reality it was closer to 2-4 hours/month)