In response to this question, I found NO restrictions last year. We stayed on Pincenardiere, which shares an entrance with Dairon and Beausejour at the Porsche curves roundabout. Whilst there were checks being done, they did not seem to be searching for bottles, cans or alcohol in any form. I did try to ask WHAT exactly they were searching for, but my mixture of bad french and shouting in English did not return comprehensible answers.