it is ok until they are signed and off the board. period. if the other school was coached by the buddy who helped you out that might be kind of ******, but other than that fire away.
Also, IMO there is no real difference from D2 to D3 for prestige, by which I mean that it goes D3 A, D3 A+, D2 D-, D2 D, etc, with each being about 1/3 tougher than the one before. Also, I don't place a whole lot of stock in D2 prestige anyway. Its about money, which you should have more of as the higher division team (barring big disparity in open ships of course), and spending it efficiently for the distance. If you have those 2 advantages almost any D2 or D3 prestige differences are secondary...