It takes five minutes or less to call up your credit card company/companies to let them know that you are going on a trip, and it can save you from tons of stress and financial worry.  The last thing you’ll want while you’re honeymooning is for the fraud department of Capital One to shut down access to your card once it notices a bunch of purchases made in a foreign country.

Even if you’re just traveling in the U.S., you should still give them a heads up.
Seriously, just do it.  Better safe than sorry, right?