Changing the name wont cause the game to crash, but there may well be conflicts if another mod changes the same cell. I'm sure I read somewhere on the Wiki that cell names are only a reference and not actually important to the game itself.
Don't worry about changing cell names though - you have to do it really otherwise you are going to find it really hard to navigate to places in the editor!
MVK
To clarify, the cell's name in the CS is only useful in the CS (for locating that cell) or if you are using scripting that requires a specific named cell. Otherwise it isn't useful. If you're actually intending to change that cell in some way "adding/removing objects, changing terrain, changing the cell name won't add any conflicts which wouldn't still exist without it. However, you should probably only change the names of cells you want to edit, and should probably limit it to just changing the name of one cell which you are editing, for ease of finding it, as opposed to changing every cell.