I've been commuting by motorbike for many years, on and off, and I'm currently doing J4 of the M3 into London, just over 25 miles. I filter past literally hundreds if not thousands of cars each day, mostly between lanes 2 & 3. Sometimes there's virtually 10 miles solid of this.
Occasionally, maybe 2-8 times a day, someone spots me coming up behind and moves over to give me a bit of space. I like this because more than anything it shows that they've seen me, so I like to thank them for it, thing is, there's no way I'm letting go of the bars to wave thanks at them, so I nod my head in their direction as I pass. I've been doing this for years, but I've never ever seen or heard of any other motorcyclist doing it.
If you were the driver, do you think you'd notice, or am I wasting my time?