Each of the 20 recipients had something to return, literally:

For example, that “important C++ component” was an allocator, which is “returning” the word taco (a popular type of street food). (“Allocator” has 9 letters and “taco” has 4, which is alluded to in the price.)

The first 20 return items – and their matching recipients – are as follows:

• 1 giftee, streetfight (one of the major scenes in West Side Story)
• 1 taco, allocator (an important C++ component)
• 1 biting, ignitible (seemed ready to go off)
• 1 reneged, degenerate (total reprobate)
• 1 ballet, tellable (worth repeating)
• 1 senior, heroines (Captain Marvel & Black Widow)
• 2 caress, tesseract (4-dimensional solid)
• 1 egret, detergent (laundry room staple)
• 2 animal, laminate (inexpensive type of flooring)
• 2 cartel, singletrack (narrow bike trail)
• 10 tacit, masticator (heavy machine useful in forestry)
• 9 rating, dignitary (distinguished ambassador)
• 1 seceder, predecessor (person who was here before me)
• 7 sneer, smithereens (remnants of an explosion)
• 6 omelet, telemovie (Duel, or High School Musical)
• 10 draught, mouthguard (often-wet piece of equipment)
• 4 tuber, rebuttal (counterargument)
• 6 acetone, enoteca (cozy wine shop)
• 7 tango, cognates (le supermarch, il ristorante and el dinosaurio)
• 9 rotative, levitator (person hovering a foot off the ground)

Taking the inidcated letter of each recipient gives an extra clue: “…said the dairy producer”. This is the person we need to match up the un-numbered 21st item (the good luck charms). And that person is a cheesemonger, who is returning some gnomes.

That was a tough one, congrats to those of you who figured it out! Just remember to hand in your nametag to the gateman when you leave :-)