I think you're getting a little pedantic now Headofthehive, but I will answer your questions as best I can.
As I've said before, based upon the fact that I have only ever met ONE adult female with unpierced ears I would say I was 99.9% certain at the time of piercing that it would definitely be done anyway at some time in their life. As an estimate, I'd say probably 95% certain that they would be asking for it done as children. Again, because my that has been my life experience. All my friends at school had theirs done by the time they hit secondary school, so age 11. All of my friends who already had children in adulthood, the girls were already begging to have it done.
I'm not discounting the fact that the three of you say your experiences have been different, but I believe you are in the minority.
Now yes, given what I've written above there is a small degree of uncertainty BUT that is true of absolutely everything in life. Nothing is 100% certain.
I believe getting it done earlier is safer, purely based on the fact that an adult would be doing the after care as apposed to a child. Yes, I believe that would stand up to scientific scrutiny . . . not that it would be necessary, because that's just common sense.
I believe in an adults right to consent, but I also believe in the rights of the parent to consent on behalf of their child until they are capable of informed consent. That is a very difficult line to draw, because children will reach different levels of maturity and understanding at different times. But I also believe that a good parent knows their child best. The example of vaccinations is a good one here. Should we wait until children are capable of consenting to being stuck with a needle and injected with an unknown substance? No, of course not. The majority of us opt to consent on behalf of our children and in their best interest. We are all charged with making the best decisions that we can on behalf of our children until they reach an age where they are capable of doing so. That's our job.
If either of my children had said 'no', they didn't want it done - then they wouldn't have had it done. From as early as 1.5 my children both had excellent understanding, communication and vocabulary and were speaking in full sentences. If it had been the case that I'd had to cajole them or, heaven forbid, hold them down . . . then it wouldn't have happened. But that was not the case.