Ok, we've been talking about it behind teh scenes, and the percentage is supposed to apply to all income, Shadow or otherwise. the reason being is that in Shadowrun, money is almost entirely digital. Which means it all gets tracked. Even those certified credsticks get tracked. So even when you're dealing on the black market, things have a way of being traceable. When you're SINless, you can get away with this, because you don't leave a record behind. the only advantage there really is to not being a part of the system. But when you're a SINner, you're part of it, even if you keep your shadow life separate from your SINning ways. And the IRS (or the corporate equiv) watch money VERY closely. And if they see you with money or expensive things that you shouldn't afford, they're going to start digging, and then you're in trouble.
Keep in mind it was the IRS took down Capone and a number of other crime bosses, while the cops and the FBI couldn't.
So the long and short of it is, SINner means you MUST pay taxes on all the money you earn off each Shadowrun. Payable at the end of each month. This will get added to the FAQ in the next revision. If you took SINner, you can drop it and take a different negative quality, or just go into Karmic Debt and pay it off.
And yes, this makes the quality not very worthwhile to take. It's going to add a fair bit of record keeping to things. But that was the intention of the flaw, so we'll stick with it.
And yes, you can argue that runners would find ways to keep things hidden and secret and only pay taxes on part of their income, and that they use Fake SINs for a lot of stuff, and etc, etc etc. But keep in mind that if you have to burn or drop a Fake SIN, you also don't currently lose the money attached to it either, because that would be nasty. So if we start diving into one end, we have to start wading through the entire pool. and deal with the upsides and downsides of shadow accounting.
We might see some advanced rules dealing with all of that in the future. But if we do, it's down the line quite a ways, and will likely be optional rules and will likely be a lot of added complexity. So for now, we'll stick with things as is.
Bull