Stae, ya it seems that this fellow will have to make a judgement call on options.
Good luck
This isn't the first time that I've read of this issue with trailers. I suspect the most common solution is just always having to find something solid to park against, just like most of us do with full panniers (or I just lay the bike down)
I agree, but it is harder for him. The thing is that laying the bike down isn't a big deal for us, but for him it is a bigger deal if it would require unhitching. Also I can imagine that it might be a bit harder to find a place to lean the bike with the trailer attached in some cases. He needs a place to lean the bike where there is room for the trailer behind it. I can recall many parking spots where the bike barely fit.