The Objective

How do you slow a villain down and ideally prevent the removal of any items before the Security Forces or keyholder attends?

You could hide the valuables to stop the villain from finding the goods he was after, or secure the valuables to prevent the villain from being able to remove the goods from the site for, say, 30 minutes.
Even if it were practical, the removal or hiding of valuables is not sustainable in the long term. Bolting everything to the ground or wall is equally impractical.

A method of protecting the property for a sufficient length of time to allow the Security Forces to respond to the alarm was required.

The solution

To cover the area to be protected in a fine vapour, reducing visibility to less than 30cm - practically nil visibility - then to maintain the density of vapour and the nil visibility until an authorised person arrives and switches off the alarm. In other words a smoke security device --a Smokecloak.