Pretty much. If you're in a rec league and your goalie can't make the game you have to scramble to find one, or forfeit the game (or play without one, which trust me, sucks for both teams since the other team feels like they have to take it easy on you even though they really shouldn't.)

Usually the league you're in provides this service though, there's a sort of standby list of goalies that can get called on if you know enough in advance that yours can't make it.

Goalies also almost never pay the league fees (the team distributes the fees amongst the skating players and doesn't make the goalie pay). Not having a goalie is basically the death of a team.