Well, people have to get in first. Which means that they don’t have something that disqualifies them from entering. Then they go into basic training. And if they lie about disqualifications and get in under false pretenses, if they pass basic, the best that can hope for is that they are kicked out instead of jailed. The Marines is rumored to be the hardest, as you know since you asked this question on several other sites. What you are attempting to enter is on the easier end of the spectrum, as you already know.