I agree, but only to an extent.
There is really zero prospect of any Central Belt LA reaching Tier 1 and for that reason the tier system wouldn't appear to be working.
The only thing that does work is a full lockdown, and if we were to go down that route, to prevent people travelling to Highlands and Islands it would need to be across the board.
A full March style lockdown is pretty unpalatable but at this point, and with furlough available it would, to my mind, do a whole lot more than the ineffective tier system.