One part of the tutorial dungeon is a 'puzzle' with pressure plates where you learn how to split the party. I haven't tried doing this by placing objects on the plates but this is the first scenario that springs to mind.
I've successfully completed this puzzle with a solo character. I had to use one of the heavy water barrels though (the regular barrels and vases just weren't heavy enough to register).
The only problem with this is, I've modded my game so that my character can carry much more weight. If I were playing an unmodded game I might not be able to pick up and carry the water barrel.
I think this is something to do with the pressure plate itself, this particular plate requires much more weight than the ones you encounter earlier in the dungeon.
