I know the scout can not take a full attack until he enters the Borken Dervish PRC. Does not the ninja's sudden strike also suffer that limitation?
Guide with knees only allows the rider to keep their hands free. it does not enable a full attack [melee] if your mount moves.
Guide with Knees
You can react instantly to guide your mount with your knees so that you can use both hands in combat. Make your Ride check at the start of your turn. If you fail, you can use only one hand this round because you need to use the other to control your mount.
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If your mount moves more than 5 feet, you can only make a single melee attack. Essentially, you have to wait until the mount gets to your enemy before attacking, so you can’t make a full attack.
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You can use ranged weapons while your mount is taking a double move, but at a -4 penalty on the attack roll. You can use ranged weapons while your mount is running (quadruple speed), at a -8 penalty. In either case, you make the attack roll when your mount has completed half its movement. You can make a full attack with a ranged weapon while your mount is moving. Likewise, you can take move actions normally