When you paint with a broad brush you tend to go way outside the lines. The experience that you describe is your experience. I will agree that there are numerous P & R folks who do not know what they are doing to the level that they should but I can tell you that my experience is that there are way more volunteers who do not do it right.
What you describe is exactly what we face here but in reverse. The park district in most cases goes in and fixes the mess ups of the volunteers.
Like I said your experience is yours and mine is mine and it isn't fair or accurate for either of us to generalize.