Could be plain old grooming, for all we know. Building up a trust factor. CM likely wouldn't want to go off for the night with him if she didn't trust him.
And mum likely wouldn't have approved it, if she didn't trust him. (I think mum likely took that pic through the caravan window during that holiday.)
There is a case that I followed here - Cherish Perrywinkle - where a friendly stranger befriended a mum and her little ones, took them shopping for things they usually couldn't afford, then said he'd take Cherish to a nearby Maccas and buy them food.
He walked straight past the Maccas, with Cherish skipping along happily with him. Cherish was found shortly after, assaulted and murdered, in a nearby church grounds.
That was a classic case of grooming. imo
(Cherish's mum is an Aussie living in the US.)
GUILTY - *DEATH PENALTY* FL - Cherish Perrywinkle, 8, Jacksonville, 6/21/13 #6 *GRAPHIC*