[iamsomewalrus]

(Amazon employee but not doing anything related to deliveries)

UPS drivers pee in bottles while out delivering, too.

In another life I worked facilities at a UPS distribution center and my team would have to pick up those bottles :-/

When yah gotta go, yah gotta go.

[dannyr]

Is it possible that they did this because there's just no easy access to restrooms like being stuck in traffic?

I have friends who have done this when they were stuck in traffic.

I imagine that when UPS drivers do their deliveries like in the suburbs, there might not be public restrooms nearby.

[cmonnow]

Logical explanation!

In reality, like always, it's a mix of both - meeting delivery deadlines, and meeting nature-call deadlines.