Can buy items when maximum carying capacity is already exceeded
In the shops, you can buy excess items when you cannot carry them.
You can buy crossaints, pains au chocolat when your maximum carrying capacity (I believe 10) is already reached. When you do so, you spend rupees but don't get anything in return.
The same is true when buying potions in the little shop on Rupee Island. When all 3 bottles are already occupied by potions or fairys, and you buy a potion, you just waste your money and don't get a potion.
I have not tested it with the monkey that sells you bananas.
XD2 version: 1.1.1 Solarus version: 1.6.0