The problem is bikers who claim they are filtering, because they know it comes with a protection that other roads users have to watch out for filtering bikes (Rules 160 and 211 put the onus on drivers) for pretty much every passing manoeuvre except the overtake of one moving vehicle. Rule 88 states "Additionally, when filtering in slow-moving traffic, take care and keep your speed low" and that is what I take filtering to be, passing through the gaps where there are slow moving vehicles. That is further clarified in Rule 211 which states "It is often difficult to see motorcyclists and cyclists, especially when they are coming up from behind, coming out of junctions, at roundabouts, overtaking you or filtering through traffic." Overtaking is different from filtering which is passing "through". Filtering means you are going through the gaps as the traffic is moving slowly forward. I would respectfully suggest that everything else should be treated as overtaking with the additional care that requires.