Well, I'm living a first-world upper-middle-class life of relative comfort and safety, so there are lots of things I wouldn't do for a hundred million. At that point, the potential payoff doesn't override most of the class of things that I would feel a lifetime of guilt for doing, and/or things that would alienate me from my family and community. I just don't *need* $100M that much. There is, I suspect, an exponential decay from about $2-3M upwards, since the difference in my life between $10M and $100M isn't necessarily an order of magnitude. I think $2-3M is my boundary for "fuck you" money.
So, things in the category of "wouldn't do" would include:
things with a high likelihood of me ending up imprisoned for more than a year or three (assuming I'd still have the money when I got out).
*Maybe* not things that have a high likelihood of requiring me to go into lifetime exile to a non-extradition country. This is a maybe since for $100M I could bring people I love to visit me in NZ or something. (So I guess I probably shouldn't rape a drugged out 13 yr old at Jack Nicholson's house)
Things that result in me directly and pre-meditatively killing one or more people who did not need killing.
I mean, I recognize that I'm already living a life that is - at some level - built upon the exploitation of people ranging from migrant farm laborers to slave-labor employees of high tech Chinese sweatshops, and living in a culture that is contributing to the destruction of the marine ecosystem as we currently know it.
There's lots of things that current-me thinks hypothetical-me would turn down $100M for. All of the ones I've imagined so far are in universes so bizarre that it's not clear the entity making the choice would be "me".
In most of my imagining, however, the offer isn't "Accept X and get $100M free and clear, or walk away and live your normal life", it's "Try to do X and get very lucky and maybe you'll be able to score big and live in hiding until caught, but if you walk away we'll kill you and everyone you care about".
There aren't many conceivable actual choices involving that kind of money and _NOT_ involving other incentives or costs.
I have turned down job/partnership offers that might have had payouts in that range, with decades of hard work and insane good luck. I estimated at the time that the EV was only a little more than working a regular (software-regular, that is) job, and the hours and risk were much worse. That wasn't "turning down $100M", it was "reducing my chance at $100M from almost zero to even closer to zero".
The only real way to find out what someone would do is to make an offer. With as little as 1% down, there's a whole lot of things I'll do that I won't do for free.