The problem with adding fiberglass tape to trainers is that most new fliers don't know that they need to remove the covering to apply the tape. If they put the fiberglass tape over the covering it will be useless because the tape will just pull away with the covering. So if they cut back the covering to apply the tape then they now have another thing to do that they don't have material to do it with, which would be recovering over the area you removed the covering from to apply the fiberglass tape.

As I said above, using a good 30 minute epoxy on the root ribs to glue the wing halves together will make the wing strong enough to stand up to just about anything that they are going to throw at the wing. The epoxy joint is going to be stronger than the wood it's attached too and more than likely the wood will fail before the epoxy joint does.

Hope this helps

Ken