Take a march, for example. It is possible to add or subtract rolls and rudiments within the style without being a distraction. It's great to keep kids at every ability level engaged, just like how we revoice clarinets or have flutes play an octave lower. If you've never had to do this, please consider that some of us work with small populations and challenging instrumentation in and out of pandemics.
In my opinion, the stage is for a prepared performance. Let the sight reading judges evaluate the snare drummer's reading abilities.