Open question/s: Would you find it useful if we made it possible to withdraw custom amounts like before? We could implement a checkbox that you'd have to click acknowledging that in certain cases you may not benefit from the same level of anonymity if you withdraw a custom amount.
I think almost everyone would want the
option to choose their withdrawal amount. A simple text-notice that privacy is enhanced when the withdrawal amount is not customized is probably sufficient. I don't think there's any need to overthink it by making it something that you have to click on a check-box or in an alert box or anything. There are some great web design tricks to convey something important like this without requiring the user to take excessive, extra steps like clicking a checkbox. And it's counterintuitive, but sometimes we actually gloss over the text associated with a checkbox (think how reflexively we click "I agree to the Terms and Service," probably often without even reading that line). If the checkbox is in the way of a user completing a form, they quite occasionally just click the box without reading it.