Hi Wifey -

There is risk, and calculated risk.

I've done this many times at FRA over the years, to the point of going into town on the tram for various items. Aviation books inside the terminal, gifts for home or destination countries, LH Worldshop luggage, etc. All in a short period of time.

True the first time is an experience. In your case it seems relatively easy.

As mentioned, you can cut the risk by calling or emailing the FRA LH Worldshop, verifying the Rimowa items you want ( model, colour, size ) are in stock, or can be ordered for you, and prepaying the lot ahead of your travel date. I would do that.

You then have a contact sales representative by name to deal with, a record of your transaction, and the item(s) on hold for you. You stroll into the store, produce your documentation and ID, the items are brought to you from the back for your review, and out you go.

Should you miss your flight, they will hold your items for you. Should a price increase occur, your items have been paid for, so no increase.

Wifey, I have done this in under one hour. So you can too.