This is a bit surprising to see indeed, given how dangerous European wild boar can be. Usually exhibits with such animals are secured a bit better.
That said, maybe many people that would visit a place like Natuurpark Lelystad would know enough about wild boar not to get into the enclosure?
We do have European wild boar in the wild in the low countries and their populations have been growing in the last years there have been some incidents and some public discussion about those, so the species is sort of in the public eye.
