Hmm... I wouldn't go so far as to call this theft, but I do think it's an egregious move that I discourage. Mind you, I get it: this is Wal-Mart we're talking about. there's more complexity at play here than simply chalking up any case of beating Wal-Mart as beating a giant, monolithic entity. Saving $340 on a PS4 isn't just $340 coming out of the Walton family's pockets. If it was, then maybe I'd feel better about sticking it to "the man."
But the reality is that price matching isn't a system in place to match pricing errors or phony internet listings. I don't know what the level of accountability is, but I think most people understand that getting such a thing price-matched is a mistake. A $340 error typically isn't something that results in people in suits shrugging their shoulders and going "oh well." Typically if it's happening repeatedly. Maybe the manager or the employee will be fine because the mistake seems honest, or it's deemed not an error at all because of strict adherence to the policy. But really, most of the time someone's going to have to be held accountable.
And that bothers me. The people that are going to get grilled over this aren't the exorbitantly rich Walton family. It's probably just low-ish level employees. And I just feel like this creates an unnecessary nuisance for them. You know, I waltz in there and give them a hard time insisting that they honor their word when I know that what I'm doing isn't on the level. I'm not trying to ride around on my high horse here. I do think there's a lot of instances where consumers should stand up for their rights and not be bullied by corporations. But stuff like this just reeks of annoying entitlement to me, particularly when some prove particularly persistent.