Yep, if you get it wrong, you visit a farmer.....
Your friends then come with the glider trailer, help you to remove the wings, load it up, and you all stop at the pub on the way home, after of course apologising to the farmer
But that is not the intention. These days gliders have good performance even into wind, and a cross country triangle typically is planned to end up where you started, saves taking it apart.... On a good day a lot of gliders will manage tasks between 140, 300, 500 kilometers, depending on weather and skill. In the UK several pilots have flown 750 k. I'm pretty sure in exotic places the 1,000 kilometer distance has been achieved...
If the weather or whatever lets you down, a field is chosen; size (large) surface - (not recently plowed) slope (don't try to land downhill, doesn't work). Cows are OK, so are sheep. Horses can be expensive. Crop is OK if you can see the soil through the leaves....etc etc.
About 30 gliders ended up during a regional competition in a couple of fields north of Birmingham. That evening the local Police rang the competition director (people see a glider in a field, must be an emergency). Said the Officer of the law to the nonplussed Director...."The next time you plan to have 30 gliders landing in my district, we will require 24 hours notice in advance......"