Amusing thread, as a landscape contractor who installs lots of plants and fences right along property lines, I kind of see both sides. I also was a roofing laborer for a short time many years ago.
That said, we are extremely careful to respect property lines, sometimes going to great lengths to do so. It is the best way to avoid trouble. And I HATE tight lot, in town jobs, and always add a significant PITA factor to the bid on them, if I bid on it at all.
Mature nursery stock is expensive, especially if professionally installed and warrantied. Does not take much damage to rack up $200, as that will get you a medium sized shrub or two, or a small tree. Nice perennials cost around $20 each installed.
Around here these days, with the exception of a few high end hand nailing crews, all the roofers are foreigners with little regard for any niceties. They leave so many nails around their job sites that I've had to get a nail sweep to protect the tires on my equipment on sites they have worked on. We charge that to the customer, and point out how messy their roofers were, and let them deal with them.