The stadiums should definitly be removed as they aren't just a map icon but also a checkpoint at the stadiums that does nothing. But IMO the pay n spray icons should be removed also. There shouldn't be any default map icons because they can all be readded by the server owner. Here are the exact pay n spray icon coordinates from the main.scm so if they are removed people can use these coordinates to readd them.
$449 = Marker.CreateIconWithoutSphere(63, 2067.4, -1831.2, 13.5)
$450 = Marker.CreateIconWithoutSphere(63, 488.0, -1734.0, 34.4)
$451 = Marker.CreateIconWithoutSphere(63, 720.016, -454.625, 15.32
$2649 = Marker.CreateIconWithoutSphere(63, -1420.547, 2583.945, 58.031)
$2650 = Marker.CreateIconWithoutSphere(63, 1966.532, 2162.65, 10.995)
$2651 = Marker.CreateIconWithoutSphere(63, -2425.46, 1020.83, 49.39)
$2652 = Marker.CreateIconWithoutSphere(63, 1021.8, -1018.7, 30.9)
$2653 = Marker.CreateIconWithoutSphere(63, -1908.9, 292.3, 40.0)
$2654 = Marker.CreateIconWithoutSphere(63, -103.6, 1112.4, 18.7)