[lxgr]

Just put it in your wallet and/or luggage. Without your account name and password, it's useless to any potential thief.

[justinclift]

Lots of people's luggage include enough info to work out their name and likely home location, which is commonly enough to work out their username for a lot of popular services.

That makes the whole "stolen luggage" thing even far riskier. :/

[lxgr]

But hopefully your luggage does not contain your Google account password.

Again, the recovery code is one factor.