Should Electrum users give out their master public key? I have seen a recent service advertising that users can turn their Electrum Wallets in to a "Cold Wallet" by providing the 3rd party service the Master Public Key from the Electrum wallet.

Ignoring the "Cold Wallet" aspect, and besides turning over complete wallet privacy to a third party what other reasons should users be encouraged to do this or not do this?
Users should be strongly discouraged from doing this because it makes them targets for robbery and extortion. Knowing a user's Electrum Master Public Key is equivalent to knowing all of their addresses and being able to look on the blockchain to see if they're worth robbing.