Will a bunch of highlighter ink washout of my white cotton t-shirt? Well, will it?

Well, will it?
Better cleaners? Cleaning Authority or Merry Maids?
Answers:    Here's a great 'how to' on removing highlighter from fabric.
You'll know how to get it out!

http://www.ehow.com/how_2089021_.html?re...
Time Machine?
Try a pre-wash stain remover - that alone should work, but if it doesn't, bleach the shirt.