I ring then the night before to leave the gate unlocked, unfortunately we as window cleaners are low an the priority list, so occasionally they forget, I either do 1 of 2 things, gain access by ladder ( weighing up the customer themselves first) or just do the fronts.
Depends whether you rang and they forgot to leave it open or you don't ring and this occasion they just weren't in.
But there are always the funny folks who moan at anything :