I have thought this was a mistake all along. I've spent plenty of time on gondolas. Most recently, we've been visiting a ski resort in northern Idaho the past few summers and ride a long gondola there. Outside temps are usually in the 70s-80s with very little humidity and it starts to get toasty in there about midway up the mountain! Now, I did see that @bioreconstruct tweeted yesterday some approximate times for each route (his projections based on a gondola transit system in Bolivia) and the longest one is only 3 minutes 49 seconds. So, assuming no breakdowns, you're not going to be up there very long at all. But, there are likely to be some stoppages, so those passengers in the heat and humidity of summer are going to bake when that happens!