Now we're talking! First of all, I've never heard about using edge for hacking without a deck. I wouldn't allow it. But even then, maybe he has a cheap deck and uses edge. Now, in my opinion, nothing money-related would ever be stored in a device. Sure, you could tamper with a reader (if something like that is even needed, could as well be all software) and mess with a single transaction. But money just passes through it. The account system you mention would be something that runs on the host or maybe off-premises in a different, central host. So here you're confronted with host ratings again.
How much edge does Joe Everyman have, anyway?
Yes, obviously you'd have to have a lucky Joe Everyman to hack without a deck into even a simple device. But, the possibility is still there, right? It's a huge security flaw.
And, okay, let's pretend most transactions are just data passing through and not held in a device. You could still hack the camera to turn it off while you pocket cred sticks, or products. Rating 2 camera, single hack for a mark, single hack for a Control Device. Suddenly you can do anything you want with no camera feed. It's just all very... silly. There's nothing strictly coming against the gameplay of the situation (though Host ratings seem pretty easy to bypass with consequence-free Hack-On-The-Flys), but the premise of focusing so much on security as to have patrolling spiders, IC, Host ratings, all to ignore the very silly bypass you get freely to all visitors.
PS I also dislike the idea of using Edge to hack without a deck. Another RAW that seems awfully silly considering the background they built for the Matrix and the universe at large.
The dangerous part of hacking a file is that it is protected
For the sake of argument, let's say we're turning off cameras to do something illegal, rather than accessing files directly. Doesn't change the premise that it's a huge security hole. But if we say it's a camera, we have two Sleaze actions which, if successful, are never discovered. If they fail, Mr. Everyman reboots and gets some rest to try again another day.
To put all of this another way:
According to RAW, at worst, you can hack any device bypassing Host defenses with freely given public Host marks. At best, you have to use a consequence-free Hack-On-The-Fly repeatedly until you get in, and you're at the same point as before.
My guess of RAI, or at least what I think should be RAI, to get access to that camera, you'd need to jack in, physically, to *something* or face a serious Host defense from even a low rating Host. Camera, lock, register, refrigeration unit. It'd require stealth, being clever, and proximity. While the previous scenario allows someone across the world to hack the devices, this one would require proximity to bypass Host rating.
For Shadowrunners, this changes nothing as you'd likely be using a physical jack to get into a host in a shadowrun in the first place (since most runs likely wouldn't be against your local store), so nothing would change. For some tech savvy wannabe-ganger, this goes from two really simple Sleaze hacks for easy access to a much more tricky situation where he/she must be much more clever to break security. Rather than just pressing a button for "Get Free Store Invite Here". Frankly, I like the change I suggest much better than the RAW.