The communal gardens at my block are frequently used as a dogs' toilet area by various dog owners who live in adjoining streets.

It's been an ongoing struggle to persuade the management company to do something about it - although I'm not sure any amount of 'no trespassing' signs will put these people off.
I find it infuriating and upsetting - my mum's partial sight loss as a child was caused by toxocariasis.