No Diagonal Sitting?

Jeepneys are the major mean of transportation in the major streets in the Philippines. There are large jeepneys that are capacitated of bringing 20 passengers while some small jeepneys (multicab) can accomodate only 13 passengers.

At times that passengers enjoy seeing the view outside the vehicle, there's a moment that the passenger will sit at a diagonal angle. It will be a consumption of space on a small jeepney or multicab. What's funny there is that though a passenger knows that the jeepney is full, he/she insists a diagonal sitting position and he/she is the one who's very mad if requested to sit properly.

This is just a common incident inside a jeepney. I thought that it's only No Diagonal Parking for parking spaces should be known to everyone, but it also needs to emphasize No Diagonal Sitting inside a jeepney to minimize space consumption.