Many of the lawns I do are not the kind that something can easily be rolled to. I feel sorry for the mowing guys who have to 2 man carry a reel mower onto a lawn. This is what happens when everything is built on the side of a dormant volcano. Everything has some kind of extreme grade to it. My kneecaps are at 16", the height I prefer to spray at. So holding the boom at that height is alright. If we want to talk about not being able to maintain a height, I believe golf courses have it bad. They have to drive a boom over ground that has all manner of hills, mounds and valleys. The greens are the only flat ground. In order to keep height, their booms would have to articulate at 2' intervals.
Not too long ago, I power raked and deep verticut my bermuda at home. It has been raining for 2 weeks straight and the sun might not come out this week. The bermuda was growing well in February, now it looks bad. One of the hardest things to deal with is that it never gets cold enough for the grass to go dormant. But the grass can be deprived of sun for long periods of time. Last year was the worst. Even the sod growers had trouble.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738