"Sixt's Hilton code D343260360 is for the German car rental company. Car rental corporate codes at hotels present an unusual dynamic — Sixt is a corporate account as a travel partner, not an employer benefit for its own staff. No FlyerTalk thread discusses Sixt Hilton employee verification. Car rental company codes are low-enforcement at all hotel brands: hotels see Sixt as a booking channel partner, not a confidential employee benefit program."

"Berkshire Hathaway's Hilton code N0437015 is a holding company code. Berkshire Hathaway itself has very few direct employees (fewer than 30 at HQ) — most employees work for subsidiaries (Geico, BNSF, etc.) that have their own corporate codes. No FlyerTalk thread documents BRK Hilton verification incidents. The holding company code is rarely used since most Berkshire subsidiaries maintain separate travel programs. Minimal enforcement expected."

"FlyerTalk's dedicated Hilton FedEx thread provides community data: "Hilton is hit or miss about checking for special codes. I have used several codes, all real, and have been asked maybe 20% of the time to show proof." Another user: "I honestly can't remember the last time I made a reservation without some kind of corp code. I have never once been asked to show any sort of ID." FedEx reportedly monitors Hilton usage volume, which could affect contract renewal terms. HotelCorporateCodes.com rates this as "Sometimes.""