So the bidon culprit has, probably due to pressure by his 'friends' (don't know if he still has any), gone to the nearest police station to admit he wasn't very bright in his mind.
His excuses are the recent death of his father-in-law (I wonder what his wife / girlfriend will think about his mourning rituals), maybe some alcohol (99.9999% sure) and maybe a bad youth (he has ginger hair so RedHeadDane could chime in and give her expert experience opinion what that does with young innocent people --> they could end up on a cycling forum!).
He is (or was now?) a member of none other than a Matej Mohoric fanclub (*), and they came with a full 50-seater bus to watch the race (and probably have some beers).
It's actualy quite a feat that he threw the bidon straight in MvdP's face without seeing him coming (you need excellent timing for that, maybe he should try a baseball career) and it's probably even a bigger feat he went unnoticed with all the smart phones etc, with that ginger hair.
(*) no bad word about the fanclub. They seem, from their socials, to support each and every rider, and advertised the bus on facebook with a picture of them encouraging MvdP last year, on exactly the same spot as they were this year. So it seems to be an attack of a lone wolf (no QS joke).