It's in your best interest to add a clause/statement to your service agreement that requres the customer to contact you within a specified time frame regarding allegations of theft. There are several reasons for doing so, but the main reason is for your protection... especially in this economy.
Think about it. Suppose Mr. & Mrs. Smith are currently 1.5 months behind on their mortgage. They decide to scam your company by accusing one of your people of stealing Mrs. Smith's $5,000.00 wedding ring, knowing that their own jewelry insurance policy will pay the claim within the next 6 weeks or so regardless of a theft conviction. Although your bond policy requires a conviction for payment, their policy does NOT require anything more than a police report.
The next time your people service their home, Mr. & Mrs. Smith can simply bypass calling you and notify the police directly that the ring went "missing" on cleaning day. Next thing you know, your company and your employees are under investigation for theft, while Mr. & Mrs. Smith file a claim against their jewelry policy. Their insurance company receives a copy of the police report, and they receive a check shortly thereafter for the insured value of the ring... and catch up on their mortgage payment.
Keep in mind that cleaning companies can be victims of theft too. I could go on with other examples, but suffice it to say that you should always CYA to the greatest extent possible. Outline the steps the customer should take when there are allegations of theft... these steps should be listed in your service agreement as a deterrent against false allegations and to give you some power and control over the investigative process.
A prospect who cannot agree to notify you promptly so that you can begin an internal investigation yourself is one that you do not want as your customer. If every customer who misplaces something goes straight to the police, then you will appear highly suspect as far as the police are concerned. Just remember that you can be a victim too... protect your business and your reputation with a well written policy regarding alleged theft.