A distressed cow just runs.... fences mean nothing.
About three years back my neighbouring farmer went away for the week end and two of his cows decided to go walkabout (leaving me to try sort it out). The cows were distressed having just been taken away from their calves and moved to a different farm. They broke through 7-wire fences like you would walk through cobwebs, smashed up about 15 fences and ended up many farms and about 7km away.
Once they were settled down though it was easy to drive them home, just walked along behind them giving them a nudge now and then.
Hence the need to get up high.... this wasn't just daisy munching buttercups in the field.