Defense Cloud

During an event the other night, I had a brief olfactory encounter with a waterless urinal.
While I know that waterless urinals are environmentally fantastic – they save literally tens of thousands of gallons of water a year – I also think that they can smell extraordinarily bad.
The instant you put one to use, in other words, you're made instantly aware of all the people who have been there before.
In fact, the experience made me wonder if you could prevent burglary by making houses smell like that: no one, not even a burglar, would come near.

If you could make your house smell like urine, in other words, all your possessions would be permanently safe...
So I was thinking, specifically, that you should attach some kind of scent-emission device to your home burglar alarm – or above the windows and beside the front doorway – before you go away for the weekend. You then just have to choose what scent will be emitted; you type in your PIN; and you go.
Because then, if someone actually does break into your house... an invisible puff of scented air – a defense cloud™ – goes misting out into the hallway, settling down onto your erstwhile burglar – who thus finds himself greeted with an alarmingly strong scent of urine. The scent gets worse by the minute, and seems to be coming from all sides.
What is this place...? the burglar thinks. Do they manufacture waterless urinals here? He recoils in horror.
But should the determined home invader persist in his folly, the scent-alarm simply kicks it up a notch, through different aromas, making everything that much worse – moldy potatoes, rotten chicken parts, gangrenous limbs and human corpses – till only someone without a nose, or a true sociopath, could even contemplate sticking around.
In which case your scent-alarm phones the police.
Only a few unfortunate customers have reported product malfunction.
A scented car alarm is now in development.