The Final Push
As you get toward the end of your project, a few things will start to change.
1) There will (hopefully) be that art lock I mentioned, meaning no changes can be made to the environment art (no new objects, no moving old objects) to allow final lighting. This is especially critical if you're lightmapping. (If someone moves a large object, you may have a huge baked shadow being cast from an object that's no longer there. Time to re-bake the lightmaps.)
2) Perforce lock: It's pretty common for Perforce to get locked as final days approach. This means you can't check in any changes you've made, and instead need to get approval from a supervisor or lead who will verify it's something important. At this point everyone is super careful, lest new additions break something. Fortunately, lighting changes rarely break anything, although it is possible, based on how complex the engine and the lighting processes are. Still, you'll need to get approval to check in final lighting changes. (If you do break something, a meaningful description of your Perforce check in makes it easier to track it down and roll back that change.)
3) Final polish: Lighters could also be described as "finishers". Usually, the lighting artists are the last ones to touch a level before the game ships. This is the time for any final lighting tweaks, post-processing changes, final color-grade adjustments, etc. Last call for alcohol.
4) The sign-offs on all the shots at this point at the lighting meetings are considered final. Approval means that's how it's going to look in the game. While there are always additional minor notes that could be made to improve things slightly, time is running out and it's important that there's an overall high and even quality to everything, rather than nit-picking a single shot to death!
