Well that's the trick isn't it? Convincing people to sign up for something because another group says they shouldn't even if it takes money, many of us have sworn to avoid similar mind-hacks but the ones who haven't may find something to use here.
If you were to actually attempt that approach, I think you'd get a reduction in signups because it would make cryonics seem even more cultish and anathema to mainstream norms, reducing the number of potentially amenable people who would consider it at all.
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: