Random thoughts:

1. Purchase a reasonably decorative cabinet a'la Jamstigator's, put a lock on it, arrange it so the vents/filter aren't easily visible, then place a noisy humidifier/dehumidifier/air ionizer on top of it or a noisily ventilated PC next to it. Find a spot where it doesn't look out of place. Avoid placing a 6-foot wardrobe next to the living room television, for example.

2. Arrange a pile of sorted laundry around the cabinet along with a laundry basket, sewing kit and chair. Alternatively, partially disassemble your bed, stack the pieces around the cabinet and leave a few tools out. Variations are endless, but the idea is to make it difficult to reach the cab without making it look like you want it to be difficult. Drawback: after a few visits, the super might notice a pattern.

3. If the visits are only about every other month and your jobs will allow it, alternate taking days off so one of you is there when he arrives. Playing a radio to cover fan noise and hooking a pair of pants on a hanger to one corner of the (locked) cab should be plenty of 'cover' if there's someone there to discourage invasive snooping and the cab doesn't look bizarrely out of place. If you don't mind direct deception and are a decent actor, making a show of being ill and retreating to your bed when he arrives might encourage him to skip that room and not spend much time in your apartment.

4. I like the casters, but not for inspections. If your superintendent were to find a large rolling cabinet jammed crossways into a walk-in closet, he might find it strange and become curious. Similarly, if for some reason he opens your door despite the sign and finds no snoozing Sunnyvale, he might become really curious.

5. Don't skimp on the odor control! I have a full-fledged vortex-fan-and-carbon-can setup for only 3 plants, and as I note in the last post there's still a trace of scent when the Ti2 CFLs are off. If your chosen solution leaves evidence, cook something strong-smelling and leave the pan in the sink when you head to work. Corned beef brisket, for example, reeks and is also tasty.

6. No, I mean super tasty. If you use idea #5, I demand a piece.