In practice I would always get out of my cab and ask someone to move, perhaps I was in the minority - the only exception would be if there was a full size pushchair (ie a big silver cross thing or similar), or if there was already another adult or juvenile buggy there (they were few and far between to be honest). I was never one for tolerating granny barrows or walkers as an excuse to not move.

In terms of ramps not working - it harks back to the electric ramp days mostly where sometimes if you'd clattered the front corner on a sweep or similar, even if it had checked out on first use check the things were often so tempremantal it would only come out so far and then pop back in - frustrating to say the least. For broken ramp hinges - should never leave the depot - it's a first use check PG9, and too be honest you can hear a failing hinge on the flip ramps as it's more of dull thud rather than a bouncy spring. Solo SRs were prone to the bonding failing on the edge and as soon as that started to happen it's a full ramp replacement. Some routes are not suited to middle door ramps as they are just not safe to deploy with the infrastructure.

Until the 2 spaces were implemented on the enviros I always though about what if two friends who were in wheelchairs wanted to travel together - never came across it in my time, but I always thought about what if.