Your client starts generating new addresses immediately to replace those used from the reserve pool. You must replace the wallet copy with the original again and again before there is any possibility of a new pool addresses being used.
You will of course lose information if you add addresses to the address book or label addresses in the wallet copy and then replace the copy with the one from the original computer - you can't use it for the basic functions you would want in a wallet.
The alternative is to never copy them, then both wallets will become independent and eventually will have their own unique addresses. Change sent back to one wallet may not be spendable in the other, the balance of one wallet may suddenly drop.
TL;DR - a bad idea.