What I Did Wrong
3/15/12: Assist Operation must be done by a registered sprite. The assist only lasts for as many combat turns as the sprite's rating, so a sprite would not be able to assist a Probing the Target test (as the interval is either 1 hour for VR or 1 day for AR).
3/1/12: Upon further review, a GMC Bulldog (a "step-van") will be henceforth be treated like a UPS delivery truck, or that SWAT van from Terminator 2.
3/1/12: From now on, I am going to rule that damage from stun attacks (stun glove, stun baton, stick-and-shock) will stage higher based on net hits, mostly because I don't see anything in the rules that suggests that it wouldn't.
3/1/12: The adept power Counterstrike does not need to be used on Full Defense; it applies after any successful parry or block (p.176 Street Magic).
2/23/12: The rules for throwing a grenade back are found in Arsenal (p. 163): Complex Action, Agility + Reaction (3) Test to pick up the grenade, Agility + Throwing Weapons to throw it elsewhere.
To this we'll apply the normal modifiers (visibility, injury, etc), plus combat movement modifiers: -1 if you have to walk to the grenade (i.e. within 3 meters), -2 if you have to run to it (8 meters).
2/16/12: Shooting the tires should probably have fallen under the "area not protected by armor" clause of the Called Shots rule (p.161 SR4A). That would have made the shooting modifier -10 instead of -4.
2/16/12: Full-auto is not eligible for called shots (p. 161 again). Called shots are for SS, SA, and BF only.
This will be an ongoing log of the rules or situations that I messed up. My goal is to improve everyone's understanding of the game, especially mine. This will be updated as I screw up something new, or when I retroactively learn about something that I screwed up previously. Please feel free to inform me if you notice something.