Fifth Wheel
by Kegler

When read normally, the overloaded squares reveal an appropriate phrase, in an appropriate way.

Fifth Wheel grid

Across
1Criminal's system briefly sells haircuts (7)
5Mexican-American in love, embracing one... (7)
9...appearing in whodunit with fool (6)
10Unusual part on bike something that might complete a set? (5,5)
11Ella, for one, and Ed dispersed (9)
12Searching, coming around, starting to believe (7)
14Arrest petty frolicking in outdoor celebration (6,5)
16Georgia reflects on Confederacy's ultimate distress (5)
18Plays guitar and two of the drums after the introduction (6)
20Referring to Carol accepting tip and starting to object loudly (8,2)
24Diminish what is being taught, we hear (6)
25Receivers of assurances combat rage and look in the mirror (10)
28Distinguishing acidic trail somehow (11)
29Finish at a salon by admitting crazy world (4-3)
30Posed method was first (7)
31Beginning to doubt corrupt reeves have it coming (7)
Down
1Cartilage of the knee in some women is cushioning (8)
2Trouble in Washington, overwhelmed by Hawaii's principal aquatic animal (3,5)
3Disallow it; her editor's cut and dried (8)
4Fur sale includes beaver, initially (5)
5University student cracked code (4)
6Annoying IRS, obtaining check at last, initially overcharged me (7)
7Staying away from helping, drinking a couple of vodkas (8)
8Individual's biological development proceeding to Germany, heartlessly (8)
13Ante up, hothead? (4)
15Father swallowing bite of meat plain (5)
17SOS! Bride's misplaced strips (8)
18Tall Dominican trio comprehends extremes of hunger and slavery (9)
19Thoroughly defeated, famous uncle comes back religious (9)
21Swirling up, red gown is explosive (9)
22Open competition put Scrabble piece in icebox, reportedly (9)
23Returning later, carrying new video from Blockbuster, perhaps (6)
26One food shop making a comeback did poorly (5)
27Cooled down a little police dog (4)

Solution