I don’t know about all localities, but in our state, LdH is often available in 375, 750 and magnums, and this is a better example than many where having some of each is a nice spot to be in.
(Admittedly, not everything is available in every given size at any given time, but our importer loves LdH, so we get options…strike when and where you can.)
I just take the foil all of the way off, and ram the cork all of the way back in. Then, no one can say that it was opened, it’s just a wine without a capsule, and the restaurant is protected from the liquor control board. If they still have a problem with that then find another restaurant.
Just a quick note on LdH reservas and vintage variability…I recall that when I met Maria Lopez de Heredia (a wonderful human being by the way) she said that the reservas are often a blend of different vintages as they are aiming for a consistent house style. I believe that up to 15% of the blend can come from vintages other than that on the label.