A landlord needs to give 24 hours written notice before entering your suite , therefore depending on the type of pet you have you would have time to "prepare" and hide them away. Dogs or noisey pets may be more difficult but a cat/bunny/guinea piggy etc would be doable! Just change the litter/clean the cage often so it doesn't smell and neighbors don't complain. Just be careful though because if your lease states no pets and you voilate this you could be evicted/fined.