Question for those who have been to a few shows

[ThunderHappens]

I logged on tonight to ask this very question!

How/when do people in the front row usually approach the stage? Do they walk on up upon arrival, slowly gather, rush up when the lights go down?

I've heard about a "cricket sound" being played....?

What bracelets? Where do you get them? Is this their only purpose?

Sorry to ask so much, but this tour will be my first Mac show, and I'm beside myself with excitement! I humbly ask all you experts for advice.