I have heard of it...It does NOT work !!
I do not recommend the use of any such spays on lures...For rods, reels etc, I use CRC Tackle Guard (and if CRC want to throw some dollars at me I might have more to say ).
There are lots of commercial "scent" additives for lures. Some work and some don't....WD40 is not one of them !!
You can make your own...I do !!
You need a bucket and a sieve and a bag of salt. You could just use some fly screen (fibreglass not aluminum). Put the sieve on the bucket, make sure it fits. Then into the sieve put any scraps of fishy things you have...prawn heads and shells, fish pieces etc. (fish guts are not good but fish offal like roe, heart, liver, gills etc is). Cover with salt and leave for a few days. The salt will draw out all the moisture and oils which will collect in the bucket. You then have a liquid dipping sauce for your lures...and the dried out salted pieces can be used for bait
itsaboat mate...Life is just a boat and then ya marry one !