Yadda yadda, I wanna buy stuff legally on my 'legal' fake SIN.
Go right ahead.
Shadowrun
assumes you want to use stuff illegally. Its rules are couched in such a way as to
presume that. Its rules say, "Okay, if you want to buy a pistol / sport rifle / cyberdeck / ChibiThulu fuzzybot, this is what you have to do in order to cover your tracks." You want to do it 'legally', using your fake SIN? Great. Here's the kicker - when you do that,
you burn more than the SIN. Using a legally-bought anything leaves traces
as you go. Can you go down to FancyPants and purchase something Ridonkulously Expensive? Yeah, yeah you can with your valid SIN - but you better make sure it's rating 6+, because that's the level of credit- and ID-check they put you through TODAY, and if you think a top-end retailer takes flashcash/certified credsticks in SR without sending a full holo of your ugly fraggin' mug down to KE, Lone Star, and every other cop shop operating in your district of the Sprawl, you got another think coming.
Those ARO tags are all talking to each other
all the time. You can say you're shutting it down, and sure, you do - but there's a
friggin' record, and that 'legal' gun sends one last 'hey, I'm getting shut down!!' yelp to Central. Turn it on again, and the thing will send right back to Central what it's done and where it's been. Why?
Because that's what they do. Going into the black market is more than just buying the damn weapon or vehicle, it's making sure it isn't going to be blabbing an event report to its home databases every time it's turned off and on.
In addition - and maybe this is just me - but there are safety measures applied to certain things. You think you can hack with your legally-bought cyberdeck? Sure you can, and the beat cop from outside your doss is going to give you dump shock by unplugging you after every system you hit screams your location. Likewise, your legally-purchased car is going to be able to be turned off remotely, your fraggin'
gun - if legally purchased - is going to have all the Peace Officer Overrides (POO!!) still active, which means Johnny Cycle Cop is going to hit an AR button and shut down your superfast motorcycle, then hit another and turn off your 'burned SIN' legal gun, because you (you dumb moron) didn't go through the sorts of channels that
take care of those things before they sell them. (N.B. - They take care of those things before they sell them
in part because they'd get their asses fried too.)
Just because you turned it 'off' doesn't mean you pulled the power pack and fried the circuitry.
Is any of this in the rules? No. Is it in the fluff? Technically, I don't believe so, no. Is it heavily
implied?? Yes, yes, a thousand places yes. You want to purchase something legally, that's what you do with your High and Luxury Lifestyle. There's a
reason that crap is rolled into 'lifestyle' and not covered - because if you're anything remotely resembling a competent shadowrunner, all the stuff you use and get 'with your lifestyle' - like the car you get as part of a Middle Lifestyle, or the limo and servants you'll have with that Luxury Lifestyle - you
don't use when you're running. You purchase your 'runner' stuff seperately, buying things in back alleys, going through hoops to make sure stuff is wiped, making very, very good friends indeed with the people whose jobs it is to cater to the very rich
and very private.
You want to go against RAW, fine - but doing so means you need to internalize the
intent of the game, which you clearly aren't doing.