Question: My son is deciding between two colleges. If we put down a deposit at one college by May 1, but then two weeks or a month later, he changes his mind, can we go back to the second school and ask if they will take him then? In other words, he would accept at only one school but then ask the second school to renew the offer, a month or so after May 1. If we did that, I assume the chances of the second school accepting again are very low. True?
That's a gambit you can certainly try as long as you go into it rife with pessimism. However, working in your favor is the fact that nearly all colleges experience some “summer melt." That's when entering freshmen who committed in May change their minds in June, July or even August. Savvy enrollment managers are usually good at anticipating melt figures and are often able to end up with the exact class size they had wanted from the get-go despite this attrition. But sometimes there is too much melt, and that's where your son might luck out.
If he decides a month or so after the May 1 deadline that he's made the wrong choice, there's nothing unethical (or insanely unrealistic) about calling the second college to ask if it might still have a place for him. But what you might find out then is that it's too early for the college folks to provide an answer because the “summer melt" typically happens ... well ... over the summer. ;-) But what you probably can learn from that call is if the college is already overenrolled. In some years, admission officials discover that more students have accepted their offers than they actually wanted, so they cross their fingers and hope that a bunch of them will change their plans before it's time to give out the dorm keys in September.
Thus, if your son does contact the second college about a vacancy and is told that it's too soon to say, he should be sure to ask if the class is already more than full. If it is, this should help him put his hopes in perspective while he waits out the melting period. He also needs to understand that, if he was awarded financial aid or a merit scholarship when he was initially accepted, he may not get the same deal again.
But as a parent of a college student myself, I think that there's great value in urging your son to pick a college now, join the first-year Facebook group, buy the T-shirt and start to envision (and get excited about) where he will be living next fall rather than obsessing over other options.