Here is how off-site prepared food delivery works:
1) OKW, SSR, Moderate Resorts, Value Resorts
. . . restaurant can deliver directly to the room
. . . they do not need special permission or allowances
. . . they do not need to check in at the Front Desk
2) BWV, BCV, VWL, BLT, AKV, Deluxe Resorts
. . . food deliverers drop food at Bell Services
. . . you can retrieve it from Bellmen or have Bellmen deliver
. . . this is to preserve the tips/income for Bellmen
NOTE: Most eateries will not violate the Bellmen rule, as they might not be allowed on-site again. Some might get around the bellmen, but I would not count on it.