Lu is wrong again! The maneuver he so poorly describes is known as the "yaw kick" maneuver, and is a Design Requirement, which means that an analysis of the aircraft's structure is required so that the strength of the rotorcraft to withstand this hypothetical maneuver is documented. NO flight test of this maneuver is required, it is not done for civil certification. Check this web site, and note the design reference:
<a href="http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgfar.nsf/CurrentFARPart/19BD64232E706CBE85256613006B2C8C?OpenDocument" target="_blank">
http://www.airweb.faa.gov/Regulatory...06B2C8C?OpenDo cument</a>
Lu is wrong further above when he says the sideways quick stop is "in violation" of part 4 of the POH because only the operating limits section, section 1, is Required for compliance, the other parts are guidence but not legally required, so you cannot "violate" them.
The sideways quick stop is stressful, but usually not for the tailcone, because of that design requirement. The tail rotor blades, hub and shaft are highly stressed in a big sideslip, so one should be careful to stay inside the sideslip envelope of the aircraft (not easy, since it is usually not published. Use the crosswind limits as an approximation, and do not exceed the crosswind speed while at 90 degrees to the flight path.
Sideways quick stops can and do work, but they make LTE easier to enter for marginal rotorcraft (I would define "marginal" as those that regularly get into LTE, and also those that have only 17 knots sideward envelope).
The aircraft actually stops very little different in sideways quick stops, the drag of the tail cone is miniscule at low speeds (a 4' x8' piece of plywood at 17 knots broadside generates about 85 pounds of drag, a Robbie tailcone must be 10% of that, and 8 pounds of stopping force is not much!) Most of a helo's stopping force is the tremendous decel brought about by the tilting of the lift backwards when the nose is raised. The virtue of a sideways quick stop is that the lift can then be tilted with bank angle instead of pitch up. You can get more roll angle easier than pitch up, with better visibility and no danger to the tail rotor from the ground. For example, it is easy to bank 30 degrees in a side flare, still see where you are going. A 30 degree nose up is most unwise in most helicopters.