The above is paraphrased but pretty accurate and has actually occurred more than a few times. It is probably a good example of me trying to be a smart-ass; it is also what brings me to this:
Most of the discussions I have encountered concerning what does and does not count as body modification have born a great resemblance to the debates which occupied a large portion of my academic career over whether or not something was art. In the case of debates over art, it can often be shown that what is actually being argued is not whether or not something is art but rather whether or not something is good or bad art. Obviously, according to most theories of art, whether or not a piece is possessed of any great talent or merit is not what determines if it is art. That is to say, even though it may suck, even though you hate it — it is still art.
In the case of body modification I have found that what is often at stake is not really whether or not something is or isn’t body modification but rather whether or not it is the sort of body modification that is of concern to the parties engaged in the debate. For instance, is hair dyeing body modification? In that it is an alteration of the body it would seem that hair dyeing is body modification on its face. However, since it is not permanent and because it falls (depending on the color) well within acceptable practices many people will claim that it is not body modification. Much of these debates focused upon what other terms would be assumed to be built into or implied in their use of the term body modification. On a practical level this is often expected and quite essential. It is common to use a specified definition for purposes of certain discussions (BME is a fine example of this in its motivation and choice of what it considers body modification for content inclusion) but that definition should not be mistaken for or masqueraded as exclusive or complete.
Body modification as it is commonly used today is a fairly recent introduction to our language and seems to have emerged mainly from the communities that practice it as described. And it is within these communities that I have been able to find the most common adoption of the term and debate over its definition. The other place in which I was most readily able to find the term applied was in anthropology — where it is often used in a very broad fashion.
Anthropologically speaking, the term is taken at nearly face value. It is applied in most any case where the body of a person is in some way altered — from hair styles and body painting to skull shaping. The interesting (and important) thing about this is that taken in this way there is no record of any human culture or society without practice(s) of body modification. And it is for precisely this reason that I support some of the broadest possible interpretations of what is body modification.
I do this because it helps to break down the artificial barrier between the modified and the un-modified. I am fond of pointing out that we are all individuals whether we like it or not. By our very nature we are different from one another but there are also many shared qualities. In embracing our own unique stature I think that it is important that we do not needlessly create the perception of even more difference. If body modification is something we all engage in, in one form or another, then there are no un-modified people.
From this point, we may find a better way for those who do not choose certain forms of modification to understand the motivations of those who do. If the person who shaves, manicures, and is possibly considering a nose-job learns to see tattooing or tongue splitting as simply an alternative example of the same general behavior (modifying the body) that they themselves engage in, it may become less mystifying to them. In fact, body modification taken as part of the overall effort to intentionally create the image that others perceive when they apprehend you — especially in an effort to better express one’s self — is something that I think most people would readily accept as the sanest and most rationale thing in which a person can engage.