Most Damaging Location Mistake for New UPMs?

Hey everyone, Aiden Cross here, UPM on a few indie shorts and now dipping my toes into a larger-scale narrative. I've been wrestling with location scouting for our upcoming feature, and I've been hitting the usual learning curve. I've found that relying purely on online images can be a trap, and managing expectations around the sheer scale of our crew and gear for smaller venues has definitely been a challenge. I’m thinking about contingency plans constantly now. The guidebooks mention a bunch of potential missteps, but I'm trying to get a handle on what really bites you hardest. From your experience, what’s the single most costly location mistake a beginner UPM is most likely to make?