Theme: Send in the Cons - Take a word starting with C O N and parse it as two words with 'con' meaning to scam.
18A. Fool check writers? : CON SIGNERS. Consigners - Those that hand over, such as goods, to another's care as in a consignment shop.
23A. Hoodwink companies? : CON FIRMS. Confirms - Verifies.
36A. Swindle court appointees? : CON JURORS. Conjurors - Ones who practice magic.
52A. Mislead groups of vacationers? : CON TOURS. Contours - The outlines of an object.
57A. Pull a fast one on proctors? : CON TESTERS. Contesters - Ones who dispute an issue.
Argyle here, no lie. I like the five synonyms Jerry came up with for "con". Very similar to last fall's puzzle gimmick except for that. (Sept.)
Across:
1. Corp.-partnership hybrids : LLCs. (Limited Liability Company )
5. Turkish title : AGA
8. Prepare for a trip : PACK
12. Icy-road application : SALT. related; 68A. Word before fall or ball : SNOW
13. Intravenous substance : FLUID
16. Final or midterm : EXAM
17. Reader of product instructions : USER
20. Verbalized : SAID
22. "Do unto __ ..." : OTHERS
25. High spirits : GAIETY
29. Take out, as text : DELETE
30. Award recipient : HONOREE
31. "Give it a shot" : "TRY"
32. Papal crown : TIARA
35. Bank teller's call : "NEXT!"
39. Pail-of-water fetcher of rhyme : JILL
42. Japanese cartoon art : ANIME
43. Kenny G's horn : SAX
46. Como or Crosby, notably : CROONER. Perry or Bing.
49. Infuriate : ENRAGE
51. Prom attendee : SENIOR
54. Visit briefly : STOP IN
56. Certain : SURE
61. Evens up : TIES
63. Away from the wind : ALEE
64. Dog-__: folded at the corner : EARED
65. Grabs a bite : EATS
66. Change direction : VEER
67. Classified messages : ADS
Down:
1. Pelican State sch. : LSU. (Louisiana State University)
2. Cowboy using a rope : LASSOER
3. In a tidy way : CLEANLY
4. Bitter discord : STRIFE
5. Org. with Titans and Chiefs : AFC. (American Football Conference)
6. Doom partner : GLOOM
7. Em and Bee : AUNTS
8. Income sources for retirees : PENSIONS
9. Cut with a pink slip : AXE. Whoa! Don't like seeing cuts and pensions so close together.
10. 52-Down, for one : CAR. 52D. 1980s-'90s Olds : CIERA
11. Metric measures: Abbr. : KMs
14. "Kinda" suffix : ISH
15. California's San __ Padres : DIEGO. Baseball team in the National League Western Division. (fourth place)
19. Nana : GRAN
21. "Me, too" : "DITTO"
23. Ill. summer hrs. : CDT. (Central Daylight Time)
24. Jockey's strap : REIN
26. Before, to Byron : ERE
27. Nickname on the range : TEX
28. Nevertheless : YET
30. Big name in spydom : HARI
33. Partly open : AJAR
34. Hosiery mishap : RUN
36. Religious place of seclusion : CLOISTER
37. Black cat crossing one's path, to some : OMEN
38. Rates on Monopoly deeds : RENTS
39. Store founder Penney and golfer Snead : JCs. Snead is the nephew of the legendary Sam Snead.
40. Wrath : IRE
41. Actor Chaney : LON
43. Lizardlike : SAURIAN. from Greek (and still Greek to me.)
44. Go along with : AGREE TO
45. Ballot box fillers? : Xes
47. Quick message : NOTE
48. Unevenly notched, as leaves : EROSE
50. Paths to take : ROUTES
53. When right turns may be allowed : ON RED
55. Educ. fundraiser : PTA
57. Ohio NBAer : CAV. (Cleveland Cavaliers)
58. Cheer for a matador : ¡OLÉ!
59. Born, in wedding announcements : NÉE
60. '60s activist gp. : SDS. (Students for a Democratic Society)
62. U-turn from NNE : SSW
Argyle