I can only characterize this lawsuit as a publicity stunt. (Shocking, I know, for publicity hounds like the Brady bunch.) A lot of this is dubious legal garbage which has been picked apart repeatedly, but look at the facts.
The one and only factual allegation that the plaintiffs have, suggesting that maybe Cabela's should have known something funny was up, is paragraph 45 of the complaint: "While inside the store, on information and belief, [the straw purchaser] displayed erratic behavior, running up and down the aisles, and remained in regular cell phone communication with [the prohibited person / real purchaser] through both text messages and phone calls."
1. "On information and belief" is a critical qualifier. It means the attorney signing the pleading doesn't know the statement is true, but thinks he might be able to find some evidence of it. I won't be surprised if Cabela's has video footage of the straw purchaser acting normally, for some value of "normally."
2. I've bought guns at that Cabela's; lots of us have. Checkout takes *forever*; it's at least a 30 minute process while three different people check to make sure your ID matches your 4473 and otherwise look you over. Have I ever looked at my phone, maybe sent some emails or texts, or even talked to someone on the phone, while I've been waiting in line? Absolutely. Is that supposed to be "suspicious behavior" now?
3. Notice what *isn't* alleged. The complaint says several times that the straw purchaser listed a false address on the 4473. It *doesn't* say that the address failed to match the ID the straw purchaser presented, nor does it say that Cabela's failed to check the ID against the 4473 (which is their normal practice). Paragraph 34 says that "providing information on the 4473 that does not match the identification provided for the background check" is an indicator that the sale might be unlawful. Maybe so, but the complaint doesn't allege, not even "on information and belief," that that happened with this sale.
4. There is also a fairly cynical race card, and to some degree a class card, being played here. If you do a Google Image search for "Brilena Hardwick," the name of the alleged straw purchaser, you will find a wanted poster issued by the ATF in Baltimore, showing a picture of an African-American woman with a visible neck tattoo. So the pitch here is that the Cabela's employees (a mostly white group of people) were supposed to decide that this black woman's behavior -- talking on her cell phone in a long checkout line and "running," for whatever duration or purpose -- was suspicious enough or low-class enough that they should have denied the sale, demanded to know who she was talking to or texting with, and maybe called the police. Imagine how that goes if it turns out she's doing something completely innocent and on the level and the employee's cross-cultural spidey-sense was over-active.
I'd ask the rhetorical question whether the Brady folks want us to live in a world where (mostly white) gun store employees get to decide that black people who pass the objective checks are nevertheless too shady or too low class to be able to buy a gun, but I know the answer: in their world, nobody should be able to buy a gun anyway, and gun dealers are bad people, so who cares if they're held to an impossible standard of conduct?