Yes I don't advice carrying a lot of cash. I actually have 2 ATM cards, one US and one French. One will always work. That said, in 10 years of heavy foreign travel I can think of only one time that my US ATM card didn't work. I called American Express to urgently get me some cash. They delivered without a problem.

Another way to get emergency cash is to ask the hotel to do a "pay out" from your account if you are short. I do this often rather than searching for an ATM. Most of the good hotels are happy to help. Some may limit to $100 or so, others may go up to $1000 or more. It depends on your value as a customer.