I completely understand from the point of view of a web services manager the need to keep a site up and running 99.9% (or better) of the time - I've learnt from experience that when manually searching airline websites, 8 pm is a bad time to do any kind of heavy manual searching, while at 3 am a website is rather more responsive. I do not intend to make a time when a webserver is struggling even worse.
However, I expect the company with that website to act in a reasonably transparent way. If a company wishes to trumpet continuously how cheap its products are, I expect to be able to search through its inventory reasonably easily to find these cheap products, instead of finding that the product I'm interested in is cheap for only 5 arbitrary days out of a 5 month period (along with an exhortation to keep returning to the website to search out cheap products). Easyjet as an example is one of the LCCs that has made a reasonable good job of coming up with a website that meets these expectations. My ire is directed at websites that are less consumer friendly. Presenting a website that is frankly difficult to search was acceptable in 1999; companies should be able to do better now.
An example of the importance of search is buying train tickets in the UK. Thetrainline.com had a website that was frankly awkward to use if one was price sensitive rather than time sensitive in choosing the train to book. Gner.com came up with a website that made it *much* easier to see the prices of trains at different times, giving me considerable encouragement to purchase from their website instead.
If companies can't or won't produce a website that is easy to search or act in a non-transparent manner over pricing, then it might be worth my considering building my own tools to search a website !