According to BBC news this evening, this woman suffers from long term mental health issues and was particularly targeted to act as a 'mule' because of this. I have no idea if that's true, or not, but I think it's worth remembering that some people are very susceptible to being 'groomed' in this way.
Saying 'she knew the risks when she did it' is pre-supposing that she is of normal intelligence, could rationalise her decision and wasn't being horribly exploited/intimidated by a third party.
I do think it's worth pausing to think about things a bit more deeply before jumping to any conclusions. Of course, she may be a ruthless criminal, in which case she deserves to be punished - although I don't agree with the death penalty in any circumstances.