Floor space is usually more valuable than it first appears
A soft bag on the floor can look harmless because it seems small and flexible.
But on multi-day private-car trips, floor and aisle areas support repeated high-value actions such as stepping in and out, turning, reaching for water and helping seniors.
Once a bag occupies the walkway, action order degrades first
If every stop requires shifting the bag, stepping around it or warning someone not to kick it, the clean default movement pattern inside the car begins to break down.
Each individual delay is small, but repeated stops amplify the cost.
For vehicles carrying seniors and children, a clear walkway is part of the safety setup
Seniors often need more deliberate footing, while children can stand up suddenly.
That makes a clear main foot zone less a matter of tidiness and more a basic way to reduce tripping, hesitation and awkward exits.
Temporary borrowing is acceptable only with explicit limits
A very short repositioning segment or a parking-lot transfer may justify brief floor use.
Once the route returns to a normal road segment, however, the bag should usually be moved back instead of letting 'just for now' become the all-day default.