I might add that now in The NFL there is field standards that must be met on a weekly basis. One of them is firmness. This is determined by a machine that measures surface firmness. I’m sure it’s been used by some super somewhere. I haven’t used it personally, but they are “a thing”.
I don't know if they use the same tool as the NFL, but the PGA Tour has a device to measure green firmness and they use it to test each green multiple times per day to try and make them consistent.
It's not brand new; I first saw that level of preparation for the US Women's Open at Sebonack in 2013. They were measuring green speed, moisture content, and firmness across each green, 3x per day.
The USGA calls that machine the "Thumper."
Bob
Actually the correct name is Tru-Firm. I once called it Thumper on a broadcast of the US Amateur when I couldn’t remember the name and was corrected. It drops a weight onto the green and measures the the resistance. As we're setting up the course in the morning, the championship lead gets the results of that and the stimpmeter readings on his phone and can adjust things if necessary .
As was mentioned above, our agronomists measure the greens multiple times every day for the days leading up a championship and during it.
They use the Tru-Firm, stimpmeters and another device that measures the moisture content in the soil.
Everyday at 2:30 there is a meeting with the agronomist, championship staff, weather person and the superintendent and his staff to discuss how to manage the greens and the rest of the course for the next round.