You filter at your own risk in a bike. On a clogged motorway, I'll creep past at 20mph or so - I can pretty much come to a stop instantly if a moron pulls out or decides to get out of his car to see what's going on. That is one thing that annoys me about other bikers - burning down between cars on a motorway which is at a stand still. So dangerous.
In town if there is 2 lanes of traffic, I will go on the outside (RHS) and nip in by the lights. However a lot of the times people don't leave a gap by the curb of traffic island. And I have to hope that the car behind the lead car will let me in. However, if it's too dangerous to filter I won't. Though if there is a gap in the middle of the 2 lanes, I will go down there, if it's safe to do so and it's wide enough. I do it past police cars too and sometimes with police bikes. I always give a little nod to people aknowledging that I'm passing.
I will always thank drivers who are curteous and driving safely. i.e. I will give a nod, or raise my hand a little at a T junction as I pass a van or car to thank them not for pulling out on me, I do the same for people who let me filter, and for people who generally drive defensively and with a good awareness.
Yes a lot of bike riders don't give the others a good reputation, but dammit they are so much more exposed - let them behave like idiots and injure themselves without you being involved trying to play cop. Bikes will filter, bikes will go quicker, bikes will be harder to see. It's the way it is.
Let's at least try and be safe out there - we all share the road, it doesn't matter who you are or what you drive, let us be sensible, cautious and aware of each other on the roads. Then we can all have a laugh, all have our thrills, and go home in the evenings not shaking like a leaf through fear.
There's far too much finger pointing, "it's not me guv..." and other excuses people use. Let's take responsibility for our actions. There will of course always be accidents - because that's what they are, unfortunate accidents.
Feel the love dudes...