Your free to install a nanny cam to record all who come and go into your apartment , your free to call inspections after any reasonable repair request you have made is ignored and Like it or not , if its mechanical /structural like holes in the ceilings or leaks yes inspections can write orders and make them fix it or they will fine them or at the worst condemn the unit ( wich is way worse since in many cities condemnation also means full code compliance in order for anyone to be able to live there again ) nice thing with a nanny cam is you can indeed take it with you to another place. And when a realtor just walks in without notice go ahead and tell them to get out or you will file formal complaint against them with your states realtor licensing agency or what ever its called . LL entry well if you have it on a nanny cam showing them entering and the time and date and you didnt get notice or they do it when you are home then call the police anyway.