I can understand InnoGames's predicament with all the new accounts popping up around tombola time and the prospect of non-nugget players obtaining event items outside the framework of the rules but I would like to see a more pro-active solution rather than a reactionary one. Perhaps find a way to differentiate non nugget purchases with nugget purchases, make the non nugget purchases auctionable 30 days after the event and the nugget purchased items auctionable immediately. Holding people's money/economic freedom for 30 days doesn't seem like a fair solution to me.
Another aspect is that it kills all the euphoria (small or big) through the event, having the items auctionable immediately creates that euphoria or buzz in saloon chat and on the market and is in a way a advertising tool for the event and associated items, if players were in 2 minds whether or not to play with nuggets to obtain an item that they fancied but didn't like their odds of getting what they wanted but see other items in that category listed on the market they perhaps feel some security in knowing that if they don't get what they want they have the option of selling it and using the ingame money to get what they wanted.
Anyhow, like I stated, it's a double edged sword, I hope a better compromise that benefits the players as well as InnoGames can be reached in the future.