Here's an amusing story about bringing cash on vacation. Americans are not allowed to take more than $10,000 in US dollars out of the country - but that will never be an issue for us!
One time we were headed to Cozumel and we were at the airport and in the line to board the plane. A transportation safety officer walked by with a large German Shepard. The dog suddenly did a sharp about face and headed straight for us! He never barked or acted aggressive but he came on in a direct line. He stopped right behind my husband and sat down with his nose level with my husband's back pocket.
I thought "OMG! What in the world does he have in his pocket?!" The officer said something into her walkie-talkie and then said "Sir, are you carrying a lot of cash?" He said "Yes I am, I am going on vacation." She said "May I see what you are carrying in your back, right pocket?" He took out a big wad of bills and handed it to her. It was a big roll of bills but mostly small bills - because we have learned to bring a number of small bills to places like Mexico where it may be hard to get change.
She examined the money and handed it back to him. She said "thank you" and wished him a "nice vacation" and walked away with the dog; but I couldn't believe that dog! It was a cash-sniffing dog!