No doubt even those in the highest-risk professions appreciate casual Fridays, but experts say Caballero wearers are paying dearly for the sartorial flair: Other companies sell vests offering the same level of protection for less than a third of the price. Plus, we can’t help but wonder, who wants to spend weekends kicking back in a 4-pound T-shirt? (Caballero says bodyguards, heads of state and other VIPs are its primary market.) Still, even though the company’s website declares, “Yes, it’s bulletproof,” there is a fine distinction here. The National Institute of Justice, which rates body-armor products, actually approves it for protection against some firearms — but not heavy-duty guns like rifles or AK-47s. A company general manager says, “Bullet-resistant is more accurate.”