An enemy chain hog is shooting you, or an enemy rocket hog with a gunner is following or approaching you. In either case the enemy has to be close enough to be doing damage to you and you would be able to throw a nade on them with a reasonable throw (they should be on your radar scope). (Associated post)
If you are under threat by a chain hog with gunner, but they are not currently attacking you, you may not exit the driver's seat to defend yourself. Instead you may drive evasively or even drive somewhere they won't see you and allow them to pass you by to remove the threat.
However, if you are driving the map backward in a last lap defence, you may not exit your hog for any reason.
If driving solo in a hog, you may stop to pick up a rocket launcher only if it is en route to your next flag. You may not stop to pick up a rocket launcher if there are two or more in the hog.
~ No camping or sniping on Race servers
~ Respect the admins & all players
~ No profanity
~ No team nading/rocketing
Most of the rules are pretty easy to follow, but camping can have different meanings to different people. So here is the rule about camping:
Camping is defined as sitting and waiting in a hog, on foot, etc. for the intent of killing another player. If your life isnt in danger on a Race map you should be driving. If you have to stop to shoot to save your life this isnt considered camping.