We need to define a limit of what we consider acceptable in a cadet environment, but we don’t need to take the mickey.
Cycling shorts and lycra on a normal parade night isn’t ideal, but normal work or casual clothes is fine. If supporting an activity in public it is better (though should not be mandatory) for all staff to be “branded” - uniform for the uniformed lot and polo/sweatshirts for CI.
For a formal event I actually consider the CI branded stuff unsuitable. I have seen photos of units all in their best clobber and the CIs look like we’ve let the cleaners into the shot. Shirt and tie at an equivalent standard should be the minimum in those circumstances.