If you read AceEvent-2.0 code, you would know that all ScheduleLeaveCombatAction() does is register a function to callback your registered function when PLAYER_REGEN_ENABLED is fired. If the player isn't in combat in the first place, then the function gets called right away, instead of "storing it" until PLAYER_REGEN_ENABLED arrives.
That's all it really does. Its just a fancy wrapper for what Tekkub wrote.
The only reason why people review your library and addons is because the commit notes you put in there are hilarious, and show a lack of understanding of the wow addon events and addon system, as well as a non-intimate knowledge of Lua itself.
A famous example is when you renamed your library from !AlarLib to AlarLib (why did it have a ! in front in the first place when you can just optdep it? Addon loading order is based on file system, it is only on a NTFS harddisk that loads addons in alphabetical order, FAT32 disks certainly don't.)
Another example is when you put in coroutine wrappers. If you're going to use something in an addon, do it directly in the addon. Don't put it in a library, and then include the library in the addon, and that addon is the one and only addon that would ever use that something and that library.
Adding all these wrapper functions add to memory usage, CPU usage and in the overall scheme of things, what wowace does not want to see - inefficient code - written in the rules or whatever in the signups for a SVN account.
Fact is, addon authors tend to review each other's code on wowace, to improve each other's addons, help to fix each other's addons. Wowace is a community. Reading each other's code also helps to improve Lua and/or find/learn new ideas and coding techniques.
Everyone is willing to help, but you have to take a first step and enter the community, and ask about anything you don't know, or if something can be done in a better way.
The wowace channel has a bot that reports every commit made to the wowace SVN, so errors, bad commits, commits that break addons, etc can be checked over and corrected within minutes.