The reason for mowing and maintaining the right of way is for safety. As the nation continues to develope and move out to the country side, there will be more lawsuits due to sight / safety issues with right of ways and road in general.

The township board can easily pass resolution to such problems - as the above poster stated, if you  (land owner) doesn't maintain the ditch/right of way - then the twp will at what ever rate they decide (personally, 10 times the rate should get most anyone attention). It all starts with the township board of directors and I know if varies across the US, in our area, maintinance for safety is a priority and the township residents pay for it in their property taxes (and is quit reasonable too) . . .