There are so many spoofs out there now taht you have to check everything. Best way to see if you have any 'real' questions from ebay is to check 'my messages' in 'my ebay'. It stores copies of everything including ebay system messages.

If I respond to a question I do so by replying to the email not through ebay. If the person asking the question hides their email address then IMO its not an important question.