Mono,
I think you need to risk assess your airfields. You can download suitable RAs online. Basically you are listing all the likely scenarios that could occur and then assess on a scale of 1 to 5 how likely that hazard is and then what are the effects, consequences of that hazard. At work we use a matrix which is quite useful, you can get them off the web.
Its really stating the bleeding obvious but a risk such as someone walking across the airfield is highly likely and the consequences could be fatal. Then you assess how likely is it that a fatality could occur. Whatever the answer is then you have to do something about it by mitigating that risk by whatever method is appropriate which I suspect is a fence and signs. That is obviously at a cost to you. But your risk assessment could state that the number of airfield intrusions is very low as is the number of flights so fencing off the footpath is disproportionate and signage is a suitable response. Also handing out leaflets to the hotel might be a reasonable response since you are being proactive and trying to reduce the likelihood of someone or more likely their dog being damaged. On the other hand it could attract more folk to the airfield.
If there was an accident then you would be able to prove, by your RA, that you have considered the likely hazards and assessed a suitable mitigation. At work if we have an incident then this is the first thing that our managers ask us to provide and if we haven't done one then all hell breaks loose.