I've suggested it to them many times through the years.
Several years ago Upton got the conservancy in Central Park to take the measurements and for 3-4 years they were pretty accurate. I'm not sure who's been doing it the last four years but it's been terrible, almost always lower than all surrounding stations.
You may remember several years ago Lonnie Quinn the channel 2 meteorologist went to the park himself to measure when he knew the measurement in the park was way off. I believe central Park measured 3 inches even from the event and he went there several hours after the snow had stopped and compression had begun and still measured 4 inches and change. That's how bad it is. Ridiculous when you think about it.
I emailed Upton about it this morning. No response yet. They have answered in the past though, and they do acknowledge it is a problem, however they never seem to permanently fix it.