Rich,
Its a reality with the new enviornmental restrictions. We have a creek where the conservation authority wants 30 metres, ie. 35 yards on unmaintained long native grass. This feature runs through a large area on the site and must be crossed to access other areas. In design you try to limit long acarries like this to directly in front of a tee so that you can hit off "the peg" and have a reasonable carry. The tough part comes when the natural area crosses after the tee shot or in front of the green. A par three is reasonable, but where do you cross the hazard in a par 4, 300 out? 350 out? this is a difficult choice because you can begin to remove options from weaker players. On a par five you can front a green, but this can agian begins to limit options for the weaker player. As you can tell I have not given an answer because everything is site specific. All I can say is we have not had a piece of land without enviornmental restrictions in 10 years and I'm hard pressed to remember a course without some kind of a forced carry. Sucks when you think about it, but the reasons it is done for are gerally correct.