What would be the purpose of this question? It's too tempting to signal a contrarian "I am not in a cult" attitude by answering negatively.

You don't really believe that this question's results would be meaningless. If we put the question in and the results were 100% 'I endorse Eliezer's handling of the basilisk', would you and everyone else simply ignore this, saying "it's too tempting to signal loyalty to prominent figures and willingness to make sacrifices"? No, of course not, you would make use of this evidence and cite it in future discussions.

And if one outcome is meaningful, then by conservation of evidence, the other outcomes (like, say, 90% polled expressing disapproval) are also evidence.