Most beginners would just walk further and be shy to check, but is it common nowadays in the Netherlands to hide a cache in a 'pot' as they call it here, which looks just like where water, gas, etc Utilities would be normally. I also managed to source one of these, but not yet hidden.
See the big box in there?
This is how it would look like when not opened.
This one was close to a river, and it was a really windy day, freezing. As the size was big and the location is muggle safe there were a few travel bugs in there, we swapped some that day.