A far more unlikely scenario than being burgled by a local thief.
1. They would have to see your notice.
2. They would need to have your address from a previous transaction.
3. They would have to know the property is actually going to be empty.
4. They would have to know that the security measures made it easier to break into your house than another.
5. They would have to believe the returns would make it worth travelling from their location to yours.
Quite honestly the majority of thieves are not that bright and their small brains would have melted long before they figured that lot out. They are opportunistic in the main and operate in their local area.
If you hold the kind of stock that would attract 'professional' thieves then you shouldn't really be keeping it in your back bedroom uninsured.
Methinks you are being a tad paranoid.