Lay people can't infringe a patent even if you hand them the patent and ask them to create an infringement. Definition of lay. (i.e. if you can create something in the domain you are not lay.)

On the other hand, actual practitioners can use their judgment. The standard is supposed to be non-obvious to someone skilled in the art. For most patents, this is going to be fairly simple, just as most cases where we respect copyright are fairly simple.