My wife and I will be traveling with 2 granddaughters to Italy. We'll have an incredible time I'm sure, but its a lot of responsibility since their parents aren't part of the plan! After hearing of the family in Mexico being asphyxiated, I'm planning on taking a small lithium battery-powered CO detector along with us, particularly for our nights in apartments. I've checked the TSA website -- nothing about CO detectors or smoke detectors. Should I pack this in checked luggage to be safe rather than taking a chance with carry-on? Thanks!