EPTIf you are paranoid that your landlord might replace the tape, sign your name or something in the tape too. Best to use tape that easily rips.
if you want to be more creative you can tie a string(like thread or something thin) to something inside the house and tie it to your doorknob when you leave the house. Make sure that it's not too long so that when they open the door, the string breaks. And then you can even be more creative, and add something like when the string gets pulled, something happens. You can even add traps like a cup of water falls on them or something by attaching a string to a cup of water on a bookshelf/ladder beside the door and tie it across the door so when they pass through it gets pulled and the water falls on them.
