The rationale for the placement of the receptacle within 3 ft is that someone can use an electric shaver, or hair dryer, etc. and not lose sight of their mug in the mirror in the process. If some 6-5 dude had to extend his 6' shaver cord (and I don't know if shaver cords are 6') from the baseboard moulding up to trim his side burns he might have a bit of a problem. The 3ft rule is a pragmatic compromise.