The greeter will still confiscate the Courier's weapons even if he/she is Idolized by the White Glove Society and has been awarded membership (by Marjorie) in the White Glove Society.
If the greeter has been killed using stealth, the White Glove Society is not hostile toward you and there will be no one to confiscate the Courier's weapons for a time. Simply exit the casino, and all weapons will be returned like normal. If you re-enter the casino, there will be no greeter and all weapons can be kept.
The greeter, if killed with stealth, will respawn in 3 days. However, if he has been looted, he will sometimes appear with only underclothing, with no mask, and with no weapon.
He is the only greeter who requires a Sneakskill of 50 to keep all weapons (including standard holdout weapons).