A few years ago I was working with a major UK retailer on a refurbishment project, the store we were working on was empty and some works were due to be carried out on the roof. The roofing contractor erected a tower scaffold to gain temporary access to the roof, the scaffold was left in place over a Bank Holiday weekend when nobody was working. The site had a perimeter fence and warning signs, the scaffold had an integral ladder but the contractor fastened some Heras fencing panels around the bottom of it to prevent anyone gaining access.
Two young kids got into the site, got past the Heras fence panels and climbed up the scaffold, got on the roof and one fell through a fragile roof light - fortunately he was not seriously hurt. The Health and Safety Executive prosecuted the roofing contractor, the main contractor on site and the retailer with charges under their Duty of Care to the Public - even though these kids had circumvented a fenced site, ignored 'Building site Dangerous working' signs, got past the fence panels around the bottom of the scaffold and were actually trespassing.
The bottom line was that the HSE finally accepted a guilty plea from the roofing contractor as they accepted that there was no signage on the scaffold stating 'Dangerous roof structure - keep off' or words to that effect. There was a fine and the mitigating circumstances (ie: some effort had been made to keep people off the site and the roof, the kids were trespassing and fortunately the injuries were minor) contained the fine at a sensible level. It was clear that the kids were trying to find a way into the store for mischief and this was also taken into account.
So .. I'm not trying to frighten anyone but consider the situation above if one of the kids had died as a result of their actions - would the HSE have pressed for a greater penalty ? Then apply the same circumstances but substitute a hive full of bees as the 'danger' and a child with a severe allergy to bee stings ....
Your insurance will cover the costs of going to court, it will cover the compensation award but what it would not cover is the fine if you do end up in court as a result of your lack of duty of care.
What you have to do is provide enough mitigating circumstances to protect you in the event that you face such an event - which means taking all reasonable precautions - and which could include physical barriers and signage, although physical barriers are the preferred option and recommended by the HSE. The HSE take the view that all accidents are preventable and that someone is always responsible. In the event of an accident causing an injury or death then the onus is upon you to prove that the only person responsible for causing it is the person who was injured or killed - and trust me - that's a pretty tall order.
Do I know what I'm talking about and am I qualified to comment ? - I stood in the dock in 1996, prosecuted by the HSE, on a charge of 'duty of care' when one of my employees fell through a roof of a building that he should not have been on and was told not to go on, he died as a result of his injuries. The HSE took the view that if I could not trust my employees to do as they were told then I had 'insufficient site management in place' and was therefore guilty. I had risk assessments, method statements, training records, lots of mitigating circumstance etc. etc. but the company ended up pleading guilty and accepting the consequential fine of £10,000 and £10,000 court costs because we could not prove emphatically that our employee fully understood the danger he had placed himself in. The court costs and legal fees were picked up by the company's insurers and the fine could have been much higher, but nothing brings back a young man who died and removes the effects on his family or me - it never goes away.
Hopefully, no beekeeper will ever be prosecuted under the duty of care clause but as we follow the USA into an increasingly more litigious society and where the HSE see themselves as a prosecuting agency it could happen ...
I'm with those above who say do everything you can to limit any risk to anyone going near your bees .. and if that can include physical barriers and signage so much the better. You also MUST be insured.