In random encounters, corpses leave loot, but is there ever any crates or toasters or other interactable objects as part of the map?
It doesn't look like it, I haven't found any so far, but I keep feeling the need to check, just is case.
The only loot in the generic random encounters is the items on the npcs present whether its bandits or a trader. There is 1 or 2 unique random encounters that you will only see once with lootable containers but that is it. So if it looks like a normal random encounter you can leave whenever you like without worry of missing containers.
Oh and remember to use the Z key since it highlights interactive objects if you are worried about missing things.