Clarification on VAT Refund
 

Hello All,

I have some questions regarding the VAT refund process.

I'm planning on buying some Rimowa suitcases on my next trip to Paris. My departure from the EU will include a long overnight layover in VIE.

I will be checking these suitcases, and from what I've read, if they're through checked to my final destination, I should process the VAT refund at CDG.
How do the customs officer verify this, since I'll need to complete the VAT refund process prior to actually checking my items in. What if I intend to through check, but the carrier ends up refusing, due to the long layover?

Next, I also understand that the items being presented for VAT refund need to be new and unused prior to exiting the EU. I was hoping to transport the suitcases to CDG without their boxes (as you can imagine, this will most likely make it easier to transport..). Will this be an issue? If it makes a difference, I can keep the suitcases empty.
This leads me to my next question: After processing the VAT refund, and customs officers had a chance to inspect the items, can I then "use" the suitcases (ie. put stuff inside), before checking them in at the check-in counters?

Thanks

I don't recall the customs agents verifying (or even being in a position to verify) a claim that you're checking your bags through. You'll presumably have boarding passes/itinerary demonstrating transit through Vienna. If the airline refuses to check all the way through I can't see customs being able to figure that out.