Usually, I'm at least able to find a utility pole or a tree. At one local grocery store, I use their gas meter. I carry a thick yet flexible steel cable, in addition to a lock, in order to have the flexibility to lock to just about anything.. However there was this one time: at another local grocery store, that I found the bike rack full and no other suitable place to lock up. It was summer and teenage employees had filled up the bike rack. So I decided to just wheel my bike through the store. The door/customer-greeter employee went on a shouting tirade as I tried to enter. For some reason he was so upset by the prospect of someone taking a bike inside the store. I said something like "I can push a 4-wheeled shopping cart through the store but not a 2-wheeled bike? Do you stop people in wheelchairs too? ... and by the way, your employees have taken up all the bike rack space, can't they park their bikes inside the store so customers can use the bike rack"? He became even more upset. So I calmly asked for the manager and when I explained to her she said "please, park your bike in front of my office and I guarantee it won't go anywhere". Her office was the elevated cage at the front of the store. Problem solved. Belligerent door-greeter person went back to his station.
When there isn't a reasonable place to lock my bike, bringing it into the store draws attention to the problem. I've also gone into restaurants and told the manager that I'd love to eat there some time but have no place to lock my bike. When we go on vacation with all of us and all of our ebikes, we can lock them together in a chain in front of the restaurant we want to eat in, and eat by the window. I think that's reasonably secure. And then also I usually chat with the manager about the lack-of-bike-racks problem.
