yeah i live in an apartment too. I have a balcony and on that balcony there is a storage closet (3'x3'x8') with a door that i got a lock for. if i was really paranoid i could get a locksmith to come and change the lock, that way even if they came over unanounced, i wouldnt have to worry. I dont think you really need to worry, providing your not doing any large scale growing. is this for personal growth? or you planting lots of em? mine hasnt started to flower yet, so i cant really weigh in on the smell issue, but i think that since mines in a pretty airtight place, i dont need to worry. where are you planning on growing it? what kind of lights are you going to use? if your using high power lights like hid then the apartment landlord might suspect something in ur energy bill. unlikely, but possible. a few cfls dont use much energy, so thats the way to go.
All that said, im still quite the novice, so dont take my word for it. keep it low key and youll be fine.