First and foremost, I think it's important to highlight that there is nothing wrong with taking some time in between a death and cloning out. People need to catch their breath, let bleed subside to prepare for the emotional or tense roleplay that may come after cloning out, and of course everyone has OOC obligations that may not lend to the time required to get everything in order after the fact.
Though it would appear to me there is an issue. There is a precedent in regards to the 'bad form' that is dodging follow-up RP via various mechanics, such as vacations, which in its helpfile states rather plainly one should not vacation their character after a high stakes event. Vacations are six month long stints in which a character is taken out of the game world, and sometimes people stay months in the vat and even get close to approaching that length of time, so one might conclude it isn't much different in terms of being 'bad form' to do so.
One could even argue the vat nap is more egregious, as the vacation is a mostly IC event where your character leaves the city. Staying in the vat is an odd, only vaguely explained, phenomenon that forces players to dance around the subject of it in an awkward fashion IC. Sprinkle on that this can follow any death and result in what one might deem a repeat offender, potentially involve convenient and arguably meta-tinged return times, and is readily available to any without the admin oversight a vacation might garner.
No one wants to get permed or chain-vatted for the most part, and not logging in is the best way to avoid that. That said, I feel most of the community does its best to facilitate more RP as opposed to cutting it short through said means. I think it is in the interest of all to let things play out with the hope we stick to our 'cooperative competition' guns, and I am wondering if others feel the same or differently.