Hard evidence isnt a requirement here though, its just a bonus.
I really do think that this draws a clear distinction between our legal systems. The prosecution must prove guilt, and the defence will seek to counter the prosecution's evidence by raising doubts about its credibility or legitimacy.

Then again, we just saw a football player accused of sexual activity with a 15 y/o get convicted of one charge, while being cleared of the other, with both of the charges based on the same evidence... the word of the now 16-year old girl. I expect a successful appeal, but what do I know?