Typically a drivers license, or any government issued ID with photo.
No, unless the casino employee ask. They can ask you as you enter or while you are gambling. It isn't worth the hassle. I can confidently say they won't bother you at the slots, unless it is quite...
Will as a city, Las Vegas will be turning 100 on March 16, this year.
There are numerous trade shows in Las Vegas. Many of which are sponsored and/or hosted at famous hotels. The trade shows continue throughout the year.
The age limit is 13 with a parent or guardian, or 18 alone.
Jewelers' Circular Keystone