I had what was for me an uncomfortable experience. Having agreed to play some trumpet parts with the top-notch choir at a church for Christmas (I'm in the choir), but also having told the music director my high range (d and above was iffy because I hadn't played in that range in several months), I hoped the choir director would give me the parts in advance just so I could read through them (and he said he would). He was writing the parts himself, and didn't get it done until the last moment. He gave me a beautifully written trumpet solo (with choir) peppered with high Ds which would have been okay if I'd had that range in shape. I got the part five minutes before rehearsal and had only a chance to glance through it before I was asked to play it with the choir. (Only rehearsal before performance.) I found it very uncomfortable because I knew the ds were in there, and I didn't want to miss them, and I had to figure out how to play my way around them on the spot.
So my question is for other people, if you were given a beautiful bit of trumpet work to play that amounted in essence to something very similar to a movement of a baroque trumpet concerto, would you usually expect, or would you prefer, to have been given the part in advance so you could prepare it a little bit, or would you be comfortable with sight-reading it?