[Lunnatiicz]

You can create a zone with incognito plugin and do this.

pawn Код:

if (IsPlayerInDynamicArea(playerid, Zone) && GetPlayerWeapon(playerid) > 0))
{
  SendClientMessage(playerid, COLOR, "You can't use arms in this zone");
  SetPlayerArmedWeapon(playerid, 0);
  }
  return 1;
}

Or good, use only this.

pawn Код:

public OnPlayerUpdate(playerid)
{
 if(GetPlayerWeapon(playerid) == 38)
{
 SendClientMessage(playerid, COLOR, "U can't use this arm :B lol");
}
}
 return 1;
}