Please note that most of the ECL's for non-standard races in the FRCS have been increased through their errata. Most now are double what they were before.
1. you have a player who desires to play a non-standard PC race.
2. you are letting the PC's start out at a level higher than 1st
3. The ECL = how many FEWER levels the player has to work with.
It is possible to have an "ECL of 0". These are more the "non-standard" PC races - and aren't as easily "munchkinized" as PC races.
Once the ECL is 1 or higher, you are playing a "monster race" for all intensive purposes; and there is some advice in the DMG on how to handle such PC's