Methods for sight-singing

[comefortea]

I was just thrown for a loop regarding my school’s theory program. Apparently they do not use solfege. My question is, if I were to audition at Juilliard, Eastman, or a similar school (for my master’s degree), would I be laughed out of the room if I were to sight-sing using numbers? And for curiosity's sake, how common is it for institutions of higher learning to use non-solfege sight-singing methods? In the past, I learned to sight read with solfege, and I’m thinking I might be better off going back to those materials and studying independently. Using numbers is easier, but if solfege is what I need to know in the long run, as I imagine it is, then I don't want to be sight-singing with numbers for the next few semesters.

Thank you in advance for any responses.