An interesting point. Keeping in mind that cryonics "believers" trust cryonics with varying degrees of probability and that many or even most of them try to appear more rational to their skeptical friends by saying "The probability is only 20% but that still makes it a good bet based on expected utility", then I'd say that I've seen both behaviors. That is, I've seen some cryonicists expressing grief, some cryonicists (including myself) saying "See you later", and my untrustworthy eyeballs indicate that this correlates to how much trust they have in cryonics.

Eyeballs also indicate that someone who's more deeply involved in the cryonics community per se is less likely to mourn, regardless of what they say about their verbal probabilities. And furthermore, when someone is suspended who themselves believed strongly in cryonics, "weak" cryonics advocates are less likely to mourn that person! This may have something to do with the degree to which mourning is empathy...? Or do they, perhaps, believe just strongly enough to worry that the one will come back and be annoyed at the "condolences"?

Are weakly religious people less likely to mourn the death of strongly religious people? I'm guessing "Yes" - and it'd be easier to gather data here.