Most music programs will take some sort of an ensemble trip at some point in the school year. These can range from a day trip to the closest big city, to amusement park festivals (ala' Music in the Parks), a Bowl Game, or potentially even a longer trip out of the country.
These trips are great ways to build excitement and a certain level of mystique around your program, however they come at a cost. In some cases more like a couple mortgage payments....
In most cases there is some sort of performance involved, and frequently the performance setting is one where missing just a few students can SEVERELY IMPEDE the quality of the performance. In a field show situation, holes in the drill or missing soloists can throw a big wet blanket on the impact of the show. Want to know the easiest way to derail a marching band performance? Remove a couple of bass drums and see what happens.
Missing kids tend to drive band directors nuts - and this is pretty universal.
High school band fundraisers - done well and coordinated intelligently - can help alleviate the pressure put on families as expenses mount. Consider that not only is FansRaise a great way to buy big stuff for your program (trailers, uniforms, equipment, etc) - but also creating a way for students to pad their own accounts to offset the costs of activity fees, trip costs, etc.