Trivial suggestion- include in the survey a question that goes something like “roll a die ten times, and write the results in order here. If you would like to be able to identify yourself on this survey later, make a copy of those results and look for them in the dataset when it is released. If you want to make sure nobody can possibly identify you on this survey, leave this question blank.”
If you want to make it something people might remember without writing it down, ask them to generate a couple of words from the diceware list.
Trivial suggestion- include in the survey a question that goes something like “roll a die ten times, and write the results in order here. If you would like to be able to identify yourself on this survey later, make a copy of those results and look for them in the dataset when it is released. If you want to make sure nobody can possibly identify you on this survey, leave this question blank.”
If you want to make it something people might remember without writing it down, ask them to generate a couple of words from the diceware list.