[…] you want opinions, but you also want committed opinions. Your poll/survey/vote will erect (or fail to erect) barriers to participation, and those barriers represent a measure of commitment. No barriers = lots of votes, but high risk of Boaty McBoatface. High barriers = few votes, but from those who care.
It’s basically another example of that classic measurement of potential abuse on any online community: time to penis. Because, in any free-for-all community submission, you’re always going to end up with a picture of a penis. To rewrite the above:
No barriers = lots of participation, but high risk of unsolicited penis