We have explored this question in another thread to some extent but I suggest it is too important to not have its own thread.
I have seen posters make all sorts of excuses why the McCanns should not go back to Portugal ranging from fear of reprisals to financial hardship through to their inability to speak Portuguese. My answer to those arguments is that they are merely excuses. There is no reason whatsoever why one or both of them cannot spend time in Portugal and even Spain looking for their daughter. They won't find her in Rothley or Rome!!
They were given money by the public to help in the search for Madeleine, money which has already paid for fraudster investigators and funded libel actions against newspapers. How much has even been used to search for Madeleine properly?
My suggestion is that they get off their backsides and start looking for her properly. Tour the countries, elicit the help of the local press and population, get a reward out there and get on with it!!