I'd say almost all Leaving Topics are ways to grab attention, or to find out if they're "liked", just like the people who post "Do you like me?" topics in Drama.
I've only seen a couple of people post topics that weren't Attention-Whorey, and just saying they're leaving for a bit and want you to know.
Most were cases of the fact that they're gone for a couple of weeks.
Personally though, I find there isn't much need for it at all.
If ever I've disappeared for some time, which I quite often do, I just stop posting.
It's pretty clear you're not there if you're not doing anything. I doubt that there are many people on here who sit and worry where you are when you go away for a bit.
If I'm disappearing for a set amount of time, then I'd make an Avatar mentioning so and to see my Signature. Then include a short description within my signature.
Problem solved, anyone who wants to know where I am can find out, and I don't make an entire topic about a relatively un-important event.