Rules overview- differences between Soccer and
   Premier  Futsal rules

Comparison between FUTSAL and SOCCER

REFEREE Q & A

Why does Premier Futsal “NOT” allow keepers to throw the ball into the opponents' penalty arc or drop kick it?

Futsal is a game of possession and allowing the GK to "Hail Mary" the ball into the opponent's arc works against the possession concept.  Futsal is designed to teach the players with the ball to look for open players, the players without the ball to get open and the team as a whole to build up the attack through possession.  Long kicks or throws into a crowded area introduces more collisions, which futsal tries to avoid.

If a sideline kick-in never enters the field (it is kicked out of bounds on the sideline), why does the other team get the ball?

Since the ball is placed on the line for a kick-in, the ball is in the field of play before it is kicked.  When a player kicks the ball out of bounds over the sideline, he kicked from an in-play position to out of bounds.  Other team gets the ball.