I'd say about 50% of the med students I meet are mercenaries- they're just incredibly smart people who want to make as much money as possible by working the fewest hours. It's why ROAD specialties are INSANELY competitive and getting worse every year.
The other 50% actually meant all the stuff they said in their personal statement.
There's nothing wrong with being in the first 50% as long as you do your dang job and uphold your oath, but those of us in the latter 50% are who end up in academics and on adcoms, so you should hide the fact you're here for the money or we won't admit you. Sorry.
Now, the flipside- I wrote I wanted to do rural primary care in my personal statement, and I'm convinced it hurt me at T20s (had a 100th percentile MCAT score and all the achievements/etc, and didn't get in anywhere fancy). The thing is, because I'm sincerely interested in rural primary care, I probably wouldn't have gone to Harvard or Hopkins anyway because I would get inferior training at those institutions for more debt. I instead got accepted to a nice little rural primary care school, and life is good now.
All of that to say- just be honest, and stuff works itself out. Unless you're a mercenary- then if you want to get in, you should probably lie I guess. I couldn't sleep at night doing that, but it seems to be pretty common in medicine these days unfortunately.