I give cut grass to the goats, but you have to be careful it doesn't start heating up.
Some dairy farms have 'zero grazing' where grass is cut and fed to them, so it must all be in the handling? maybe not giving too much at a time?
Maybe the farmer was also a bit concerned you might treat your lawn with something, forget and tip the grass over without thinking?
But this thread is more about the grass being turned into silage on a small scale, as an alternative to hay in winter, it does change and has quite a smell (which I quite like because it reminds me of happy days helping on a dairy farm, milking in winter, the warmth and smell of the cows & silage.)