The problem I have with the no stop rule is that it can be very harsh. Someone can ride a section well and clean it but because they stopped briefly at noe point they should get a 5. There's nothing in between.
I think, therefore, observers tend to be more lenient. The trouble is then that the better riders then take advantage of that, knowing the observer can't give them a 5 for a brief stop as they just let a lesser rider off.
I actually like the concept of no stop trials but I think a 5 for stopping is way too harsh. You end up with widely differing scores and not much in between, especially on easier trials.
I for one wouldn't want to go back to the days of riders taking 5 minutes to get through a section balancing and hopping forwards, backwards and sideways. I think they need to stick with no stop but instead of 5 for stopping it should be a 1. No other changes required. Then you can stick rigidly to the rules and people wouldn't get upset.
I observed yesterday for the first time in years (normally ride) and I had a section with a tricky tight bit between trees where people were getting their footrests stuck. If I had applied the rules strictly, virtually everyone would have got a 5 apart from a couple that cleaned it. I ended up telling people that if they stopped momentarily as their footrests got stuck but then heaved the bike out straightaway they'd be fine. If they sat there struggling and spinning they'd get a 5. Seemed to work ok and everyone agreed but I shouldn't have to make up my own rules so everyone can have an enjoyable day.