The name is brickSpawnPointData.I believe that there's only a single argument (the brick) in ::onPlant. Also, you'd want to first call the parent, and if the client is not an admin then delete the brick.
package lol{ function brickSpawnPointData::onPlant(%this,%obj) { if(%obj.client.isAdmin) { echo("rawr"); return; } }}; activatepackage("lol");
That's why I said you have to *delete* the brick.