xtech,
I've heard that some of your more rugged designed jets and landing gear can take the abuse of grass, but for the most part I would agree with VF-84. Go to a jet fly in sometime, and look at the speed some of these guys come in for landing. I think some of them land hotter or have higher stalls then a small Cessna full size aircraft!
I would not recommend attempting to taxi or flight without a FOD screen in any jet with bottom intakes such as the Eurofighter or F-16. Not when a screen will only cost $20 to save a $3,000.00 + engine. As for the cost of the screen vs the investment of the engine, I'll personally use a FOD screen on any plane it will fit.
See Jetcat link :
http://www.sitewaveshosting.com/Merc...uct_Code=A1045
Mike