I have done the mistake of accidentally buying ‘Hero cap increase’ and I forgave it. But when I saw that the legend @Coppersky have done the same mistake, maybe even multiple times, I thought - THIS HAS STOP!
Reference to Copperskys confession : XP Level Question
I will not test what other places should have the confirmation on, but IMHO all these items should be protected with a confirmation step. Nothing worse than feeling that you have been cheated out of your money