See for me, this highlights how they ARE very different. You wouldn't catch Labour or the Tories selling a tour with their key figurehead for £150. Their lawyers would have been all over it, and they prefer selling lunches with David Cameron for £40k or whatever it famously was, taking huge...
It sounds like she has done something wrong to be honest - seems like they've been caught red-handed. Just seems naive more than outrageously dishonest to me, particularly when you look at the sums involved.
As others have said, I'm sure a walk around the Commons has probably been thrown in alongside the policy lunches, direct influence on decision-making and peerages that the big parties regularly sell for millions.
Surprised an MP as diligent as Lucas has made this mistake, but it's hardly crime...