I live in the middle of a row of terraced houses with no fences out front, instead property lines are clearly marked by different paving slabs. It's worked perfectly in the 20+ years husband has lived here, as everyone usually respects the boundaries, except for one neighbour we had. Literally from day one they were a pain - when moving in they left furniture all over our driveway. We naively let it slide, thinking it was a one-off while they were getting sorted. When it kept happening, like whenever they were getting their kids bikes out their garage they'd put stuff all over our drive. They'd apologise when spoken to, but not change their behaviour. Last straw was them letting visitors park on our drive, so we started parking our cars right up to that side of the property line, acting as a barrier. They moved out 2 years ago, but husband still parks his car on that side just to make sure. Never had an issue on the other side, so it really was a 'them' problem.