That's not something you can prove. More than that, though, it's not to say that having them removed for science is often possible and worth more than losing them in the back alleys. While I doubt that Tonsils have any special unique cells to make them of any major use, they've come up with better science for less useful things. NASA uses glass that weighs three times air for Shuttle insulation.
I mean, if I don't want skin cells I can rub some off my arm. If a woman wants to get rid of a baby, she can toss herself down some stairs. That helps no one, though.