How can you judge whether juice is really freshly squeezed?
This isn't exactly scientific but.. 

Taste. 
Specifically looking for the taste difference between pasteurized and un-pasteurized juice. Pasteurized orange juice has a  distinct tart taste that just isn't there with fresh juice. 

I guess it depends on your exact meaning of "fresh", but if it hasn't been pasteurized then it will have a shelf-life of only a few days.

The legal specifics of the terms will vary from country to country, so if you have one in mind then you might have to mention that. Although as you hinted at, the legally defined terms are often side-stepped and might not be much use.