I would burn down his shop if this happen to me.
Hmm, I could have sworn that I saw a Givi logo on a tag in those bags. They are stored away, so I'm not checking right now. Looks like Ducati gets a lot of money for their logo.
Here is another solution, from a different forum. The side cases hold 32L, and are only $100 each without the foam inserts. Adorama is one source. They are Pelican iM2450 cases bolted to a custom frame. Submersible, lockable and very sturdy. Wonder if I could make adapters for the Strada mounts...
The strada's bag-side mounts can be unscrewed .......
If you don't want to take the stock bag-side mounts off the stock bags, the mounts and lock mech are available and shown in the parts fiche. I thought they weren't, but I looked further and found them. $22 for the non-locking catches, not sure how much the lock mech costs.