A recent EU comissioned study, funded by us tax payers, came to the conclusion that reflective clothing/daytime lights/ light painwork in fact makes it more likely to be involved in an accident.
I've posted the link to the results before and I can't really be arsed to trawl the net to find it again.

The long and short of it is that if you want to ride around looking like a Christmas tree that's fine by me, but don't start making out it's the safest thing to do.