1) most likely get lower COL increases
Ya mean it'll take longer to get where you already are? No, umm, ya mean if you accept less to start off with it'll take less time to get where you are? Umm, no, ummm, (I need a time machine and paradox checker to understand this argument).
2) make yourself more expendable in a downsize
Ya mean someone should strive to be cheaper and less of a target? I thought you should strive for excellance and value, which in turn makes you cheap at any price.
3)upset alot of co-workers who will eventually find out what they paid you (should their salary be less).
The attitude of random possibly semi-competent people should affect how you negotiate? That's insane. Sure, will knowledge that you make a certain percentage more than them come out? Eventually. And before that point, you'll have shown how your skill-set and attitude is worth it, which means they have something to shoot for when their turn comes. Which should not limit what you get at all.