A strange thing happened to a good friend of mine recently.
He and his wife were sitting watching the tele when a girl simply walked into their house and started nosing through the rooms downstairs. My pal said the person appeared to be significantly influenced by drugs. She walked in through the front door and passed by the sitting room door when my pal's wife spotted her and gave chase and shouted at her but she didn't stop and it took my pal to physically man handle her to get her out of the house. Apparently she is a well known "druggy" in the area and they reported the incident to the police.
Shortly afterwards someone from Northumbria Firearms unit called to say that the incident had been referred to them as my pal "stores guns" at the house and he was advised/warned to always keep all windows and doors locked at all times even when there was someone in the house.
He is with SACS and rang them for advice and they told him that the police were right and this is current best practice, although they did tell him that he should also formally press charges for trespass.
I would be interested to hear your opinions on this as it does affect us all.