The top school knows that it is a top school for many people and it doesn't need to offer financial aid to entice some people to say yes. You might be one of those people. It might not even have much money to give and therefore is choosing not to give to people who will sign without seeing the money first.
The other school knows that scholarship money can help seal the deal and it knows that it runs in second place to "more desirable" competitors. Therefore, it "showed you the money" in the hope that you would take that into account when making a decision.
Would you go to your top choice with no scholarship at all? You might be trying to use the scholarship offer from the other school as leverage when, at the same time, your top choice school has made twice as many offers as it has seats (yes, schools do that) and it is hoping that many people turn them down. Not providing scholarship information is one way to thin that herd.
