I have various friends visit throughout the year and none of them have ever been asked about sufficient funds or a bank statement. Then again, these are visitors from Australia. Maybe this requirement only applies to selected countries.
The other thing to remember is that ‘Old’ US dollar notes aren’t accepted. I was there last year and I got a US one dollar bill in my change and when I tried to pay for something with it they wouldn’t accept it…because it was old. I must admit though, I’m not really sure what’s considered as an old dollar note. Maybe worth a google