I understand the struggle in ensuring that there should be enough room for everyone in a tent. In fact whenever I go travelling on foot, my team had to take turns to sleeping in the tent due to them being of varying sizes and weighs.

(Harry can see how tough it is for his Pokémon to draw lots on who could sleep in a tent with their Trainer. But they know that there is no point in complaining about tent sizes and share resources when not living in cities and towns.)