I play in a brass band, where the brass players are constantly noodling before a gig, between numbers, after we're done... and so forth. Some will noodle along with the background music before we go on, with the worst offenders attempting to noodle along with the band playing before us. Yeah... all terrible stuff and it took me some time to break them from these bad, and often ingrained poor habits. So I try to lead by example. With covid, I'll set up my mouthpiece at home and blow three descending tones on it while off the horn, then cap it and put it in the case. When I get to a gig, I'm the last to get my horn out. When I do, I'll run up and down the horn chromatically just fingering without blowing to make sure nothing's sticking. Then I play three short notes in succession; low Bb, middle Bb then high Bb. Then I play the gig.