Hey Doug -

these are used in some split games in LV (and California, etc), such as Omaha H/L. If the pot is "scooped" by one person (instead of being split between two people) AND the pot is greater than a certain dollar amount ($30 for example) the button is used to indicate that the next hand will be at a higher limit. There are a couple of other rules (such as the scooper having to put in a blind for the next hand).