We have signage in our center, courtesy of the safety committee warning us about not interacting with dogs in any way, shape or form. If you get bit then the company is going to tell you they warned you about it. They are just covering their rear ends as usual. How did you know that there was an invisible fence? If I at all felt like I was going to get bit with or without the fence I would have found the appropriate button to push on the diad and moved on. I on the other hand am always looking for a good reason not to deliver a package to someone who irritates me. I guess that would fall into that catagory. If you don't like the fences let the people know you have a problem with them having dogs outside when you have to enter their property. Don't tell them you don't like the fence, tell them that you are in fear of the dogs with or without the fence. Like mentioned in the previous post, the fences only keep the most undetermined dogs in. Let them know that you will be happy to deliver the packages when the dogs are safely in the house. Let your supervisor know that there is an issue with dogs at that address and they should back you up based on the policy I mentioned above. Safety, they can't deny it to you. Good luck.