I tend to avoid grocery stores who do that. But in Belgium at least it’s a known strategy that half the grocery stores use to make you spend more time looking for stuff.
Luckily there’s also a store that avoids it because they want to save time of their employees and customers. So if use their app to make your list and select the location you’re going to, the app will arrange your list to be in the order you encounter everything if you follow the lines on the floor.
It would depend on the event hall. If it was in a warehouse like hall and in spring or fall, sure you’d keep your shirt on.
If it was in a event hall with a lower ceiling, carpet on the floor and just some form of insulation it’d get crazy hot really fast. Because on top of thousands of PC’s there’d be thousands of people too. In summer it’d be even crazier. I definitely remember going shirtless at some of those lans.