There's always somebody on the bench, and it's always the coach's fault.
It surprises me how many people seem to think the fees parents pay to a travel program buy them a deed to the shortstop position and the third spot in the batting order for the entire season.
If the money you paid is guaranteeing your kid a spot in the lineup, then by definition you are playing daddy ball.
If, on the other hand, you have affiliated with a competitive team, the fees bought an opportunity to compete.
If the player finds himself sitting on the bench the last three weeks of the season, it's an indication of what he did with that opportunity to compete.
It doesn't mean the coach is a jerk or a crook or a trophy-crazed hyper-competitive maniac.
As for those who say they'd go to another program the next year: yeah, that's pretty much the message the coach is sending.
This is not the way ringers work in the sense the OP is posting about.
The prototypical case analogous to the OP is an otherwise successful team that's advanced, or advancing, deep in some big tournament, Cooperstown, USSSA, PG, whatever. They then fly in some guy(s) who's not part of the normal roster to win the big game, benching perfectly capable regulars in the pursuit of a trophy/championship that has essentially no bearing on anyone's future. See the Bryce Harper example given above.
If everyone on the team is fine with it and informed ahead of time, I guess whatever floats your boat, but if an otherwise successful kid ends up riding the pine in the big game so some coach/organization can hang another plaque/banner on the wall, that's, frankly, horseshit at the levels of baseball we're talking about here and the parents paying for it (and the players who end up on the bench) have a valid beef.
JacJac,
The OP said nothing about advancing to higher level tournaments or deeper within the tournaments they were already signed up for, nothing about pursuit of trophies or championships and nothing about the performance levels of the players. When asked about promises the coach made about roster size or playing time, the OP only referred to the "general understanding" on teams in his area, which suggests there were no promises made.
So your imaginary prototypical scenario doesn't have much to do with this situation.
And one more thing: keep your language clean on these boards.