An update: the inner rim diameter of the Visc rims is only 14.3mm while the rim strips measure 20mm in width. It's no surprise that the edges of the rim strips ride up the sides of the rim interfering with tire mounting. I have removed and reinstalled the rim strips multiple times and it is not possible to install the rim strips without them riding up somewhere. I would guess that the rim strips probably came from the factory as it's difficult to imagine why the dealer would swap out the original rim strips.
Unfortunately a set of new tires were ruined by the faulty rim strips but at least we don't have to worry about getting the rims replaced anymore which is a big relief. Going to order some 10mm Velox and expect everything to be fine. My friend is probably not going back to the shop she bought the bike from to try and get her ruined tires replaced. She just doesn't want to see them anymore. Not only did she buy the bike from the shop, but a set of Orlieb panniers, mudguards, and the Marthon Plus's. Sigh.
Final conclusions:
1) Not all bike dealers are technically competent.
2) Dahon Europe's customer support is nil. This is completely unacceptable.
3) Thor is so dedicated that he does the work of other people even on other continents.
4) Always remove rim tape when not being able to mount tire beads properly.
Cheers