you can make this
if ($1 >= 18) && ($1 <= 50) mode $chan +v $nick
if ($1 < 18) { mode $chan +b $wildsite
kick $chan $nick Come Back After Your 18th Birthday.
}
}
to this
$iif($1 isnum 18-50,mode $chan +v $nick,ban -k # $nick 2 Come Back After Your 18th Birthday.)
but as HoNdAx707 said anyone can lie and put !18