Its all about traceability. If Billy Burglar is caught with a garage of stolen items, and the investigating officers cant find any evidence that the items are stolen, which is basically tracing their owner, there is little evidence to convict him. Yes, a physical deterrent will help prevent the initial theft, but if you want the stuff back, if its seized, get it DNA marked.

https://www.smartwater.com/news/smartwater-marked-tools-recovered/

http://archive.derbyshire.police.uk...urity-marked-in-Grindleford-and-Bradwell.aspx