If you see them, give them a wide berth. Short pants are great in the summer, my poor legs get so hot. Some trails do not have any Stinging Nettles but others have many. My long pants go back on in July and stay on for the rest of the year. It is double tough if you stir up Yellow Jackets with your short pants on.
Some hikers are very happy with their zip-on legs for their pants.
Many hikers tuck their pants in their socks to keep ticks from crawling up their legs. One hiker reported a deer tick bite from a Park trip in 1998. The tick was under his arm for about two days before it was discovered and removed. The bite mark was red but had almost disappeared. After a week it started to turn red again.