SY are impotent in as far as a proper investigation is concerned in Portugal. They are hamstrung by red tape, the Portuguese call the tune, they hold all the cards. That suits some people just fine though if the truth be known.
The tapas-9 refusal to cooperate with the investigation under Rebelo only served to underline the view of many people in the UK that they had something to hide. This was a missing child inquiry after all, it wasn't a nicked wallet or camera. Nobody seems able to give an answer to my question, where was Madeleine in all of this while they were busily saving their own miserable skins?
Bottom line. Nothing to Hide > Nothing to Worry About!
In a normal world, I'd agree with you, John. But I think that you are discounting the effect of a constant drip of PJ leaks to the tabloids. What if this had happened to your family? Imagine if you and others were supposed to go back to a country in such circumstances? In an imaginary case, to somehow prove that you hadn't collectively committed an armed robbery of a bank with hostages and whatever else, with no cctv to prove that you weren't there, or even worse in the case of a missing child? You could be placed in various positions near the bank and be instructed to perform certain actions and it would have hit the headlines all over again.
I'm not sure that I'd have gone back either if I had come to the conclusion that it was more about stitching someone up than finding out what had actually happened. With hindsight, I really don't think that Rebelo or the PM were doing anything more than box-ticking, but they couldn't have felt confident about that at the time.