i think depending on the org, the reason you might have more girls at one tryout isn't the fact that there are only 1-2 spots available, but these girls are motivated by
1) seeing a team on a message board like OFC and seeing what all the hub bub is about (and it still may be fostered by a parent)...girls and parents notice who makes ASA nationals, they know who wins what tourney....why does everyone want to become a Red Sox or a Yankee? same rule applies
2) being beaten/played a competetive game against said team--this is the highest compliment of them all....getting a girl to come out for your tryout after handing them their lunch during the season? wow...and all the same teams play one another...all it takes is for that one girl who isn't seeing playing time to test the grass...when you are talking at the level of some teams, one really isnt that much different than the other, you're really splitting hairs...then it becomes location and coach's prestige/approach...i mean, seriously, if you can make Lasers/Stingrays/Wolfpack/Classics/GCKA/Ice or Extreme, i would think you could write your own ticket....if you're taking a step down, then it becomes, "will i try and get the same exposure?" "instead of compuware, am i okay with playing at ----?"
3) being recruited....and i wont get into the mind of David of any other Classics coach, but i know other coaches know the families of girls they wanted last year or have been trying to get since birth....regardless of the EXTREME loyalty, people want to win.....and there is nothing inherently wrong with recruiting...it wouldn't be travel ball without it...how you go about it, I'm sure, determines how you sleep at night