In my view this is an interesting topic but in my view fundamentally very fast electric and scale just don't mix. You wouldn't put a family car on a grand prix circuit without asking for trouble no matter how careful either party is. There may well be collisions amongst the scale fraternity but little damage is typically done. However a big fast electric can cause catastrophic damage to a scale model which has taken years to build. There is also the wash they create to be considered.
Each to their own however and clubs should make sensible provision where possible for all interests and all should be well. Separate sailing times and/or areas and just use some common sense to try to please all.
However fast electrics are noisy, one may be okay but then that typically grows into two or three and when they are on the lake no one else can use it. The very nature of fast electrics dictates a momentary lack of concentration means they have travelled 50 feet or more so which means if they are sailed at the same time as scale then its too dangerous for scale to sail. My scale models take years to build and if there is a very fast electric on the water I just won't sail as I don't want there to be an accident at all.
The reality is if clubs permit a lot of fast electrics (not talking about club 500) to sail then there will be a noise issues and complaints made and the loss of the water may typically result as councils won't take a chance and if by accident you hit a swan or goose and a complaint is made then no model boating at all. The general public much prefer swans and geese than model boats. You only have to see the outcry when a model boater complains his boat was attacked by a swan, its just a battle we can't win.
This may or may not be fair but it is the case so we all need to be mindful of the realities. Hopefully there are waters where fast electrics and i.c. can be used albeit people may have to travel more to enjoy this element of the hobby.
Fast electrics are also not what they used to be, they are now extremely fast and could be lethal if loss of control and they hit the bank and fly into the air. As regards i.c. in my opinion whilst most boaters are sensible there is always a small percentage that are not and won't fit proper silencers and they spoil it for the rest of us. Either way i.c. do have a greater potential for pollution which is an absolute no for councils. Again I do hope there are dedicated sites where they can be used for those who enjoy that side of the hobby.
Times and boat performances have just changed and we need to move with the times to preserve access to valuable water sites. If we take risks sooner or later we will loose them. Whether there is actual danger to wildlife is one thing (fast eclectics and i.c. inherently put wildlife at risk just because of their speed) but the public perception is also that there must be, (even if there hasn't been a recorded event on a particular lake), is what counts and can cost the hobby the use of lakes.
As the world moves on certain behaviour patterns that were once acceptable are no more acceptable. Typically if you ask to use a new water I would bet the answer would be no because lots of council people only see screaming diesel or electric boats making noise and pollution and they don't have the resources or will to monitor the sites for correct and sensible usage.
A little off topic but with the expansion of the ULEZ which will probably be adopted by various cities in the UK this could also kill the hobby (boats and planes) if you have to buy an expensive new car just to travel!
Cheers
Geoff