I walked the route to Grimaldo in April, 2013. I chose to go the new route, while four others decided to try the old one. When they came to the locked fence the farmer had put up to keep pilgrims out, two decided to climb over, another went further down the road to make his own way across the fields and the fourth turned back. The two who climbed over the fence were able to walk the old route with no further problems. The one who walked further down the road had an adventure "bushwacking" across pastures and fields for several kilometers. The one who turned back was met by a local policeman in a car who told him that the farmer had no right to block the trail and the pilgrim should go back and climb over the fence. Regardless, we all made it to Grimaldo.
Side note - the last kilometer or two on the new trail up the hill to Grimaldo is a bit informal. It goes through people's back yards and gardens. If you are in Grimaldo on the weekend, you have to stop at the restaurant across the street from the albergue. It was the best meal I had on the VdlP.