I always put up some meters of fencing tape and a couple of the blue posts inside their pen in the shed after weaning. They start chewing on the wire while I am still connecting it...or just run through.
Two days of noisy learning, then they are usually trained enough to go out in the field.
And there is only the electric fence, maybe a dyke or stockfence miles away.
And yes, Tape does get seen a lot easier by the piggies, specially when the bottom one of the two lines I put up for them, is tape. Also I find it easier to see from a distance if the fence is buried in turned over soil, than if it was just wire.
Plus, Tape seems a bit more elastic than wire or poly, when the wind or pigs get hold of it....