Imagine not being able to find away around 2 - 8 foot long fences?
I think you're completely missing the point. It's not meant to be a physical barricade. It's to clearly communicate the trail is closed and should not be ridden. I think it does this much better than a little wooden sign.
If someone is aware that riding muddy trails is not cool, but they just don't care, there's not much you can do about that person.
If you rode cross you'd become proficient at lifting up the tape and riding under without slowing down.