Your runners will just use caseless normally anyway. If you're worried about a gm pulling that move the system isn't your problem. The gm is.
This is a pretty clear example the Oberoni Fallacy, or at least a variant of it I can't remember the name of. From what I hear the actual rules for RFID ammo are so vague and weird that it pretty clearly is the system failing and forcing the GM to intervene to fix it, which is a clear indication of bad design.
I don't even mind the implication that RFID ammo is now the norm among normal people, even though the idea of corps forcing that through between editions is literally bonkers, because edition changes are a good place to just change the lore and mechanics backing the lore without justification, it kinda is the point after all that it is a good spot to change how things work. But from what I have heard it definitely doesn't read like 'runners don't need to bother with this' so if its intended that runners can just get caseless ammo whenever they want that probably should be errata'd in, because it seems like the implication is that you can't easily get caseless and there is no information on how you go about it, and that isn't a remotely insignificant detail.
Like... the ability of gun using PCs to realistically participate in anonymous violent crime, AKA shadowruns, without having to pass tests to tag erase bullets is kinda a big deal... Like maybe this is people getting up in arms over nothing but it sounds like there is a serious conveyance issue combined with an attempt to ICly justify a change that probably should have just been a retacon.
That said, the idea is cool. It sorta adds to the 'superpower' of being SINless, the concept that the cops are dependent on bullets telling them who shot them and helps cement the idea that runners using black market high end gear are crazy hard to trace. Reminds me of how much Android Netrunner helped build the lore just by putting "Unregistered" in front of the only firearm card in the game to impress upon you that the power of that card didn't come from the fact it was a (rather weak) pistol but from the fact it absolutely couldn't be traced to you so you could kill sys-ops and execs with it after finding their adress from corp HQ with literally no heat on yourself. It kinda pushes the idea that SINlessness and being outside the system is kinda a mystical protection runners have in a sense.