do they really require and wear do you put it …back of shoes has it
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Yes and on your shirt and shorts.
In 3 IMs (CA, LP, AZ) , I’ve never worn the reflective tape…
I’ve done 2 IM’s and have never used the reflective stuff. Though I have carried the light stick, since I’m old and finish afer dark: )
I know that in the 1997 Hawaii Ironman they had volunteers who checked the contents of your bike to run bag to make sure that your run gear had reflective material. I have not seen any other inspections for refelctive material in 8 other races over the distance. It is alway mentioned in the race booklet. I used it in my first 7 races but have not for the last 2. Thankfully I made it in before Sundown in both.
I did IMC in 92 and someone checked. I did IMLP last year and they didn’t.
However, it’s a good idea to have it anyway. You never know when your 9:30 will turn into a 15:00. 
It is required in the rules but if you are sure you will finish before sundown don’t bother. I haven’t needed it…yet.
If you’re doing a M-dot race you can buy it from InsideOut at the expo.