I read about a study in the UK that indicated bikcyclists should not signal in any way. It seems that there were MORE auto/bike accidents if you signalled. The theory advanced was that if you make some kind of signal, the driver then has to process what you mean and then react. Better to just do what you want.

Now, if you're in slow moving traffic, it should be OK to signal so as to keep Mr. Wheeler happy. But I have this feeling that it doesn't actually help at all. So, I just GO.
...thehick