[QUOTE=Struan]
That must have been a fun thing for the three of them to do! 
[/QUOTE]
Maybe, but I’m willing to bet the “prosecution” for this case did not do a diligent job.
Alison Weir pointed out that the corpses found when the tower was rennovated were described as being dressed in velvet. Velvet was unknown in the UK before the reign of Edward IV, and the only two people who were in the tower from that time until the remains were found, and who vanished and were the approximate age, were the princes. There is no one else the remains could have been.
More’s account, with someone who claimed to be in on the plot, predicted where the bodies would be found. It’s hard to argue that it’s false if it comes up with something that is discovered years later (the person talking to More described dropping the dead princes in the stairwell where the two corpses were discovered; he said he was told the bodies were moved later, but was not present, so it was just hearsay that they were moved).
There are also eyewitness acounts that the princes were seen in the Tower (which, as now, was a public are) after August of the year. Plus the king stopped paying their jailer around the time the princes vanished.
I doubt Richard killed them personally, but he clearly gave the order – he had a strong motive, since it would have put an end to all opposition to his reign*.
This is a fairly typical reaction to any historical figure that gets a bad reputation: people start saying, “Well, he couldn’t really be that bad” and start looking for excuses that don’t exist. Richard’s evil was definitely overstated, but he was a cruel and impulsive man who had other examples of killing those who were threats to his power.
*At the time, Henry Tudor was an obscure prince living in France with only the most tenuous of claims on the throne (he was not the true Lancastrian heir, which at the time was King Juan of Portugal) – one of the reasons why Henry never claimed his crown due to right of blood, but rather because of Right of Conquest.