The trouble is, there is no written record of the word 'picnic' used in England until 1748, and even then it was more drink than food related. Picnics as we know them were a 19 century pastime. (on wiki so it must be true).

I think the original words were ~ that they 'rested' there, on May Day. Which is a pretty loaded statement by any standard. It implies informality and intimacy at best.

I'm not easy with an oak tree being 'honored' either- what does that mean? People have honour, not trees.

To me it sounds like the oak of honor was so named as it is the place where they want you to believe that both the queen and Sir Richard Bulkeley acted with honour and integrity on that May Day 1602.

And to be fair, today 'honor oak' sounds better than 'fornication oak', so alls well that ends well, really.