I'm not sure what "outlaw" is supposed to mean, but, no, med school is tough enough, and time consuming enough, that you are not supposed to be working while in med school. Work is work. 60 hours a week at a hedge fund. 20 hours a week at McDonalds. However many hours a week in your bedroom working on your app.
That said, nobody is going to be cross referencing your tax returns, other than, of course, for financial aid purposes. You've already said that you have an extensive investment portfolio that will presumably be generating income while you are in school, so merely showing income on a tax return is not going to set off any bells in any event.
Otherwise, if you are brilliant enough to handle everything, you should be fine, but I wouldn't want to be the guy seeking help in the student resource center, to avoid having to repeat a year, while explaining that you have historically been fine academically and just under estimated just how difficult med school would be when making time commitments to your app.
I get that you seem to enjoy living on the edge, but it was only a few short months ago that you were worried about the realization of your life long dream being unfairly denied to you because of a youthful indiscretion. Now that you are back in the game, after an involuntary multi year delay, you would "like to start developing an app before med school starts"!
My humble suggestion would be to put the horse before the cart, and hold off until AFTER med school starts. Not only to conform to the expectations or requirements of the school, but, more importantly, to be able to see how much free time you actually have before making outside time commitments. What's more important to you -- being successful in med school, and putting yourself in the best possible position to be accepted into the most competitive specialty possible at the best possible med school, or getting a jump start on a side hustle? JMHO.
If you are worried at all about getting into "trouble," either academically or administratively, you don't need to post questions about the activity, because you already know that the correct response is simply to follow the rules, whatever they are. If you think an activity is "outlawed," you of all people should know that the correct answer is to not engage in it, rather than to ask questions about whether you will get in trouble if evidence of your involvement is later uncovered!
By the way, a lot of your posts giving advice to others are pretty insightful and spot on, which is why posts referring to schools "outlawing" outside activities and checking for compliance through tax returns might look like trolling to some.
