I used to do this and still do this. I cut arm warmers from cheap women's pantyhose and toss the f*ckers when the race starts or stick them in my shorts. They are for that prerace period when you are sitting there waiting to start and freezing your a$$ off but can't warm up until the gun goes off. Kinda better than the trash bags I used in the early 90's.
If you buy arm warmers for fashion, this is not blue collar. You also should never cross a finish line wearing them unless you live in Fairbanks.
Other fashion no-no's:
Compression shorts
One piece tri-suits
Bunhuggers for men
Compression socks
Ghetto basketball shorts than come to the knees
But these are acceptable:
Headbands (with a fro!)
Cotton T-shirt with track club name written on the front with a magic marker
Pistol Pete style sloppy socks
Knee high tubes with the stripes
V-notch shorts cut high on the hip
No socks!
Trucker's hat. (Mesh baby!)