In the case of Sacramento River fly fishing guide Lonnie Boles and his new Float Rite indicators, they might just come from tiki bars:
"As Lonnie casts and watches how his line moves, he especially sees how a little bobbing plastic indicator is tracking. That's Lonnie's invention he calls a Float Right, and it's a hit on the Internet. Lonnie got the idea from one of those little umbrellas in tropical cocktails."
Apparently when the stem of the indicator floats perpendicular to the water you know you are getting the perfect dead drift.
Photo via Cabela's