My CFI wasn't at the airport when he wasn't actually instructing, so the SOP was (at least after I had a few hours logged) that at the end of a lesson, he'd tell me what we'd be doing in the next lesson. Day of the next lesson, I'd get a briefing, then call him with my go/no-go decision and explain why. I don't think I ever recommended 'go' when he overruled me, but occasionally he'd suggest modifying the plan for the day based on the conditions, and he'd explain why. That was a valuable part of the learning experience. Early on, I was making PIC weather decisions, but with the training wheels on, because he'd also gotten the briefing--he just didn't share his opinions till after I'd explained mine.