Let's say I'm a VP at Google and I'm moonlighting as a consultant for startups. If you were Google and you found out that I earned $153M from this, how would you feel about this?
The VP is likely required by employment contract to submit all such relationships (contracting, consulting, advisor boards, board of directors, and maybe even angel investments) to Google beforehand so that Google can run a conflict if interest check and give their blessing or prohibit the activity.
What's Google's policy on speaking fees? Or are you just curious how people would emotionally react to find a co-worker making a lot of money on the side?