hafrashas challah and hataras nidrei nezirus

Since my wife was blogging about challah, I could not resist over Shabbos pointing out an overlap between an issue in a sugya of nezirus, parshas hashavua, and an issue in hilchos challah. The Rama paskens that if the dough seperated for challah falls back into your main pile, and there is not a sufficient shiur bittul (1/101), one possible solution is to get a Rav to be matir neder - since challah functions like other nidrei hekdesh, being matir neder will return the piece which was seperated back to its original state of tevel. What does this have to do with nezirus? Tos (Gittin 33a) asks: how can a nazir ever gets malkos for drinking a cup of wine or becoming tamei - since every nazir can undo his/her nezirus by going to a Rav and being matir neder, the hasra'ah (warning) given my the witnesses not to drink wine is a hasra'as safeik - how do the witnesses know that the nazir will not undo his/her nezirus state? Tosfos offers two answers: 1) since most people are not matir their nidrei nezirus, we follow rov, majority, in validating the hasra'ah; 2) since at the time the nazir drinks he/she is in a state of nezirus, that constitutes a chazakah and validates the hasra'ah. Putting the answers aside, let's focus for a moment on Tosfos' question. The Maharasha asks: given that unless a person were to be matir neder he/she would receive the punishment of malkos, this case should not even be a safeik hasra'ah - of course any reasonable person would rather be matir neder than face punishment!? Based on this argument, the Taz writes that indeed there is no escape clause from punishment by being matir neder. A Rav who is approached to be matir a neder nezirus not because the noder has any real regret, but simply so he/she may escape punishment, is not permitted or able to release the noder from such a vow. Similarly, argues the Taz, being matir a neder hekdesh of challah simply because now you have a ta'aroves issur v'heter and the dough will be ruined is not a justfiable reason for release from the neder. The Taz therefore rejects the Rama l'halacha. L'ma'aseh (and I can't imagine this is an uncommon occurance), see the Pitchei Tshuvah, and ask you local Rav.