What I described is standard practice for most companies, and Intel has abided by this for as long as I've been following the stock starting around '95.
Here is the text from their earnings warning last quarter:
"SANTA CLARA, Calif., March 3, 2006 – Intel Corporation today announced that first-quarter revenue is expected to be between $8.7 billion and $9.1 billion, as compared to the previous expectation of between $9.1 billion and $9.7 billion, primarily due to weaker than expected demand and a slight market segment share loss.
The company expects the first-quarter gross margin percentage to be adversely impacted by the change in revenue. Expenses (R&D plus MG&A) are expected to be lower than previously forecast due to lower revenue- and profit-related spending.
Effective with this announcement, Intel has begun its “Quiet Period.” Intel’s Business Outlook, published in the company’s fourth-quarter earnings release dated Jan. 17, 2006, and in its Form 10-K for the year ended Dec. 31, 2005, no longer reflects the company’s current expectations. The company plans to provide a new Business Outlook when it reports first-quarter financial results on April 19, 2006."
Here is the description of the quiet period on www.intc.com:
Intel’s Earnings and Business Update press releases contain certain forward-looking statements (see Business Outlook), which are subject to known and unknown risks and uncertainties (including those noted in the releases and in Intel's SEC filings on, e.g., Forms 10-K and 10-Q) that could cause actual results to differ materially. Intel will keep the current published Business Outlook publicly available on its web site, and the public can continue to rely on this Business Outlook as still being Intel's current expectations on matters covered unless Intel is in a “Quiet Period” or publishes a notice stating otherwise. Intel intends to publish an earnings release on July 19, 2006. From the close of business on June 2, 2006, until publication of the release, Intel will observe a “Quiet Period” during which Intel’s published Business Outlook should be considered to be historical, speaking as of prior to the Quiet Period only and not subject to update by the company. Intel is currently in a Quiet Period. None of the forward-looking statements in the Business Outlook should be considered as the current expectations of Intel. If we use any non-GAAP financial measure (as defined by the SEC in Regulation G) in any Earnings conference call, you will find the required presentation of, and reconciliation to, the most directly comparable GAAP financial measure below under "Other Financial Information" for the applicable quarter.
(Bold left intact from original text)
So technically, yes, the Quiet Period implies that any previous guidance is no longer valid. But whenever Intel's quarterly results have differed materially from their guidance by more than 10%, they have issued an earnings pre-announcement concurrent with the start of the quiet period. I would expect no less of them now.