Thank you very much for the question. Again, I'm not wearing a hat of any particular organization. I'm here with my hatless head today.
You're right that biosecurity expectations have changed. People used to welcome people into their barns. It was seen as a sign of friendliness. As you say now, the signs are up, the doors are closed, and before you can get into barns, you are expected to change clothes, go through disinfection procedures, and things like that.
That being said, the risk really comes if whoever is coming in has been exposed to a disease somewhere else. It's really hard, and this is one of the challenges. If you haven't been near any sick animals, and if you haven't been near any particular disease agent, then you are really not likely bringing it on to the farm. It's when you have been near those animals, or those agents, that the risk increases.
Unfortunately, we don't always know. That's the problem, and that's why farmers have implemented standards that have to apply to everybody, because they can't take a chance with your knowing whether or not you've been near a sick animal or been exposed to a virus. We can't take that chance.
Therefore, the standards are set. Mostly, they are kind of consistent across the country, but lots of them are implemented at the provincial level through various organizations, like the dairy farmers or the pork producers, setting up standards that work for their particular situation. Then they move out across the country that way.
I hope that answers your question.