Can't comment about night travel, but we've just come back from camping la Chaumiere near St. Omer through Dunkirk at midday and saw no signs of trouble. Nor did we when we went over two weeks ago. In fact, we've never seen any problems in over twelve years of using that route!
Dutch friends staying with us on site wanted to see for themselves, so visited Dunkirk last Wednesday, and then Calais on Thursday, and reported having a great day out on both occasions, without any sign of trouble.
I'm not saying there isn't a problem; there obviously is, and I fully support the lorry drivers action last week, but please don't let it spoil your holiday! Campsites around the ports are reporting a poor season, mainly I suppose down to the problems.If this continues, then the terrorists ( cos this is what they are!) have won.
We've crossed through Dunkirk and back twice this year, and fully intend to do so next year.
Rule Britannia!