The purpose of Circular 230 is to "improve ethical standards for tax professionals and to curb abusive tax avoidance transactions."
So, tax professionals include the Circular 230 disclaimer on everything, even if it doesnt appear that it applys to the instant situation. The reasoning is CYA (cover your ass!)
This is the email disclaimer that I use:
US Treasury Circular 230 Disclosure: To ensure compliance with requirements imposed by the US Internal Revenue Service, I am required to inform you that: (1) nothing contained in this message (including an attachment) was intended or written to be used nor can it be used or relied upon by you (or any other taxpayer), for the purpose of avoiding penalties that may be imposed on you (or any other taxpayer) under the Internal Revenue Code of 1986, as amended, (2) any written statement contained in this message (including an attachment) relating to any Federal tax transaction or matter may not be used by any person to support the promotion or marketing of or to recommend any Federal tax transaction(s) or matter(s) addressed in this message, and (3) you (or any other taxpayer) should seek advice based on your (or any other taxpayer's) particular circumstances from an independent tax advisor/preparer with respect to any Federal tax transaction or matter contained in this message.
Here are a few more brief examples:
The principal purpose of ____________is not to avoid or evade Federal tax if ____________has as its purpose the claiming of tax benefits in a manner consistent with the statute and Congressional purpose. _______may have a significant purpose of avoidance or evasion even though it does not have the principal purpose of avoidance or evasion.
To ensure compliance with requirements imposed by the IRS, I inform you that any tax avoidance contained in this communication (including any attachments) was not intended or written to be used, and cannot be used, for the purpose of (i) avoiding penalties under the Internal Revenue Code or (ii) promoting, marketing, or recommending to another party any transaction or matter addressed herein.
See the attached link for more details.
http://www.irs.gov/irs/article/0,,id=132445,00.html