I’ve had the opposite happen - I’ve hit implement (because I wanted to see in more detail what the effects would be) only to then realise I can’t go back, because once I have that knowledge - it’s already implemented! Worse still, because I ‘undid changes’ it’s now just sitting in the middle like a lemon 
I feel like it might be a mechanic (you can’t know the full effects without jumping in) but seen as I don’t know how much weight it’ll have on GDP, there’s seemingly no harm in me getting to play with the slider before it’s done for good.