SG4, TG20, etc. are not the law but are guidance. Or industry best practice.
If there was a fatality or major accident involving a scaffolder falling from height because they hadn't erected an advanced guardrail or a board snapped because it wasn't supported every 1.2m on a dummy lift, the director of scaffold company and any of the managers and supervisors responsible for the injured party could go to court (either magistrates or crown in uk with maximum sentence of 2 yrs prison and unlimited fines)
In court, although u haven't directly broken 'a law' your company isn't working to industry best practice and won't have a leg to stand on. Ignorance is not a get out clause.
Every company in uk must have access to 'competent health and safety advice' (which is a law) so to say you didn't know means you have broken this law.
The possibility outcome of a fall from height heavily out weigh's the cost of erecting an advanced guardrail in the eyes of any courts in my opinion so to say it isn't workable and affordable won't get you out of jail.
Although I totally agree with you that it is a waste of time and effort, and i think nasc should go back to SG4:05 with regard to adv. guard rail.
Also Tg20:08, wats the point of an advanced scaffolder if every job has to be designed?
Client: can you remove that standard so we can dig a trench?
2005 Scaff: yes no problem il spur it up,
Client: thank you, here have lots more work,
2012 Scaff no I need a design, £200 and 2 days notice please.
Client, your firm is sh1te...