I take it that you would also allow cyclists to fit short lances to
their bikes to deal with pedestrians and motorists who fail to obey
the law?

That depends on what laws you have in mind.

I rather think that my answer would be yes if you mean pedestrians and
motorists committing GBH or the like - and possibly littering

But I don't want cyclists to be able to continue making up their own
laws. (I well remember trying to cross the road during a critical mass
ride in central London. The mass ignored the red lights, ignored the 85
year old lady trying to cross with me, and told us both to "go get
f****d if you ain't got a fu****g bike".)

And IIRC we also don't have yet the jaywalking law Ken Livingstone
proposed in 2006 (which wd have made it an offence an offence to cross
other than at a specified crossing with a green light) so I'd rather
not be lanced for crossing the road. It's bad enough having getting
scratched, bruise and punched now when daring to use a pedestrian
crossing or controlled crossing in a manner which might require a
cyclist to extend his (or very rarely her) journey by 5 seconds.
--
Robin