In reply to EvolutionOutdoors: So everyone on here should moderate their language in case a 5 year old is reading it - FFS**** - get over yourself, this is an adult climbing forum!!!!
And as for my high horse, well, if berating people for using chalk on V Diffs is a high horse, then I'm happy to keep on riding it, because the fact is you don't need chalk on anything below E3 (and even then not on every move) - and it's a principle i've stuck to all my life - we're talking about a country with an average temperature of around 13 degrees, not Yosemite.
And if mummy and daddy use chalk on V Diffs, then of course their kids will follow example and do the same - soon people will be chalking up to open the boot of the bloody car!
So maybe Mr Instructor - you should spend your time educating your clients on the suitability of chalk usage on the crag, as compared to an indoor wall - instead of playing moral guardian on the use of profanities.