Actually, Drizzt could be quite a valuable bargaining chip for a party of questionable morals. If during the plot there was something that the drow had that the PC's wanted, or information they knew, or whatnot, and they wanted to bargain for it or get into Lloth's good (evil) books - well, bring Drizzt in. It wouldn't mean killing him themselves (though they might be asked to do that too) but imagine the jubilation of the drow priesthood if one tied-up ranger was deposited on their doorstep courtesy of the party! And they'd think twice about reneging on any deals they'd made before too, if the party are that powerful to be able to bring down Drizzr even with the sods horde of allies.