I don't think getting rid of the pink is going to be accomplished without dropping a few bucks, with paint or tile replacement. Gymschu is correct in that it could be painted and would probably hold up pretty well. There's usually not too much banging around in a bathroom. But dangermouse is correct in saying that it would look like painted tile. Once the tile and the grout are the same color, it's going to look solid and crappy. However, with a little patience and skill, it could be pulled off. I would suggest painting/decorating in a fashion that complements the pink tile and makes it look like that was the plan, and takes the apology out of it.