Aye. I think if you introduce the discipline of voting at that kind of age, surround it with discussions and "citizenship" stuff, but still offer the chance not to vote if you ask them to think about it and justify why not, then longer term it might just address the turnout thing.

I think most 16 year olds are desperate to be considered adults. If you give them something that signifies you trust them to act in an adult way, then they'll seize on it.

I did a bit of work as a polling clerk in the past. There were old people coming in who clearly had no capacity to really understand what they were doing or what they were voting for, it was just muscle memory. The number of clueless 16/17 year olds is probably no different to the number of those kind of people (in fact it's statistically probably a lot fewer).