Submitting a paper to a conference whose scientific committee includes an academic from a grad school you want to enroll
The chance that a rejection would have this impact on your graduate school application is extremely low.

First, check how many members the program committee has, and realize that only 1 - 3 of them will look at your paper at all during review. Second, even if the paper is rejected, there is a chance that the person handling the paper will have forgotten about the details after a year or more. Third, even if they remember, they may not hold it against you, especially if the conference is very competitive, but rather look at the positive things you show in your application.

On the other hand, think about how acceptance of your paper would later on increase your chances of getting admitted to this graduate school! This would be something that you put in your application anyway, so there's no problem with it being forgotten, and it will make a positive impression even if that particular committee member was not the one to handle your paper. It is definitely a "risk" worth taking!