Landing at a grass strip, the pilot has no way of assessing its softness, wetness, or grass length. He has to rely on information given. There's usually no qualification for the person giving this information, other than a radio licence.
I've landed and only on getting out, stepping into standing water under the grass, realized how wet it was. (I did manage to take-off, with mud splattered on top of the wings.) If arriving from a distance, you've no way of knowing how much rain there's been, or how it has drained and evaporated.