Only when the consistency is based solely on a reverence for tradition, religion, conforming to the opinions of others, the opinions of the greats of the past - in other words, something that is not really in line with one's own truth. If your past opinion is based on one of these things, it is foolish. It would fit into the "pop culture" definition of the foolish consistency that one may and should change without shame. (In Don's case, is the opinion that the Eagles should end with Glenn's death applicable here? No!) On the other hand, Emerson argues one should be CONSTANT to one's truth. But people use it as an excuse to validate every change of opinion, even when they stray from their conscience, from what they know is right.... as Don did. Thus, he violates Emerson.
The FIRST part of "Self-Reliance" does lend itself to the "pop-culture" interpretation because, again, there are SOME instances where Emerson finds such a change of past opinion justifiable - when that opinion was not based on one's own truth. However, when you read beyond the opening paragraphs, you see that changing one's opinion is not universally justifiable; as I said earlier in my summary, you cannot change from your truth to an opinion that violates your conscience. Reading further, you see his real point:
"And now at last the highest truth on this subject remains unsaid; probably cannot be said; for all that we say is the far-off remembering of the intuition. That thought, by what I can now nearest approach to say it, is this. When good is near you, when you have life in yourself, it is not by any known or accustomed way; you shall not discern the foot-prints of any other; you shall not see the face of man; you shall not hear any name;—— the way, the thought, the good, shall be wholly strange and new. It shall exclude example and experience.
[...]
If we cannot at once rise to the sanctities of obedience and faith, let us at least resist our temptations; let us enter into the state of war, and wake Thor and Woden, courage and constancy, in our Saxon breasts. This is to be done in our smooth times by speaking the truth. Check this lying hospitality and lying affection. Live no longer to the expectation of these deceived and deceiving people with whom we converse."
Admittedly, there are other interpretations, and I've only pulled out a couple passages when there are far more to discuss (not that these are the only ones to support me). However, I despise it when Emerson is used to justify doing what one knows in one's heart is wrong. I do not think that was Emerson's intent. In fact, Emerson was concerned that people would think that "the bold sensualist will use the name of philosophy to gild his crimes." However, he hoped that "the law of consciousness abides" and people would follow their truth rather than use his teachings to justify betrayal and wrongdoing, to listen to those who would "tempt" us with things like money...
Honestly, overall, Emerson has a lot of problematic doctrines, and the truth is that his philosophy is really not one to live your life by in any case. But if you are going to tout him as your inspiration, be aware of his larger point.