I myself have made trg arrangements for my troops, only to have them ruined at the last minute by the actions of someone higher on the food chain than I am, or by administrative concerns or problems that crop up suddenly. My plans get ruined, my Sgt‘s plans get ruined, my Tp WO‘s plans get ruined, even my CO‘s plans get ruined by such shenanigans, and they happen quite frequently. Last minute changes to the trg calendar, I‘ll give you this, are one of the single most annoying things about life in the reserves.
That said, it‘s a fact of life that they will always occur, because the nature of the reserves (being part time, often having less experienced pers working for you, etc) makes it almost inevitable that they will. This kind of thing happens to the regs a fair bit as well though, I can assure you. All in all, though everyone does their best to limit such ****ups to a bare minimum, they do occur more than we‘d like, and we just have to deal with it. Without ever having met a single Officer or NCO in your unit, I‘d bet you a large sum of money that none of them are actually intentionally lying to you, telling you to come in for rapelling when they know you‘re going to be doing pub amendments. They get boned the same as you.