Personally I think it is simple,
Day 1 of a tourny bottles are checked and tagged (HPAC already do this)
Anyone under 18 should have their bottles filled if that is what the UKPSF membership says - Otherwise insurance is void.
A simple 10 minute training session will soon bring anyone else up to being comptetent, and trust me guys when you get it wrong (which is very rare) the accidents are very bad, an example is if there is a pin prick of HPPA flowing out as a leak it will slice your finger off before you feel it.
The plus side is the kit is very well made and HPAC among others are very thorough, it may only be two minutes to fill your bottle but it is two minutes that you need to be sensible.
What doesn't help is where some sites have become over paranoid, but then it is there site and it is up to them