Pipeline will be used as the main example, however this tactic can be adapted to be used on any map. The objective is to secure the Control Panel in pipeline. The hardest part is always breaking into the main pump room, as there are ALWAYS some camping defence in there. This tactic is fool-proof if it is used correctly.

First objective: clear areas surrounding the main pump room entrances. This ensures that no one sneaks up behind you because there will be a point where you are sitting still waiting for the signal.
Second Objective: Designate a Squadron Leader
Third Objective:Leader Designates Entrances to specific players or squads. For example, tell one squad to secure the bathroom cooridor, another to secure west entrance, one to go main intersection, one vents, and one primary (depending on how large your team is).
Forth Objective: Seperate squadrans get to there area, secure it, report in (tell your squadron leader you are ready and are awaiting his signal), wait.
Fifth Objective: When all squadrons have secured and reached there area the squadron leader yells the signal word for go.
Sixth Objective: Each team rush's into main pump room at exact same time. The idea is to catch the campers off guard and confuse them. 99% of time you will confuse the defence and they wont know who to shoot at. Most will react by shooting at everyone rather than eliminating anyone. This means almost everyone on your team will live. View the screenshots below to see clearing assignments for main pump room; dont let any corner go un-noticed.
Seventh Objective: Secure the area - Set up a perimeter while one person gets the objective. Do not throw smokes while securing the objective you should have sufficent people to hold the enemy off for 15 seconds.

*Important Pointers*
-Be very quite you do not want the enemy to know where you are - suprise is the word of the moment.
-Create a go signal, so there is no confusion.
-Announce the tactic will be used BEFORE the round starts so that there is ample time to organize and prepare.
-This is not a good tactic if there is frequently a large number of defence rushing the pipeline entrances. This is to be used against camping defences.
-Make sure you are not on silence when you open door, you want the door to open fast so everyone can get through faster; SUPRISE. The doors must be opened all at the EXACT same time, you will create much more confusion on the defence side.
-If you do not have very many members (2-3) make sure you spread out dont all come from one side, surround the area first.
-A way to add to the confusion is thru the use of smokes. This means that 1-2 people throw a smoke (away from the door) seconds before the rush is to take place. For example, person in main intersection could throw a smoke at the corner next to the bottom of the stairs coming from the break room. Or the person in the bathroom cooridoors could throw a smoke in the shower in the bathroom, person in west entrance could throw a smoke on to the roof of the building, or the person at primary could throw a smoke halfway down primary maitenance tunnel. You DO NOT want everyon to throw a nade or it becomes excessive and unneccesary. however if 1-2 people throw a smoke I believe it will distract the op-for's attention away from the door they are watching. This would give an essential 2-3 seconds to the rushing assult.

The following screenshots detail the places you should look first when entering the Main Pump Room (in order by number). These are, in my opinion, campers favorite hiding places. Each door has a different set of areas to cover when using the rush tactic.

Main Corridoor Intersection	Bathroom Corridoor
West Entrance	Primary Valve
Main Pump Room Access