I didn't want to write about this before i was sure, and i actually had some "current" examples. Today i actually found a company, designing their pages in Dreamweaver, and they didn't even include a valid doctype.
When i first started out learning html/css (5-6 years ago), i was surprised to find "webdesign" companies who where designing their pages in "WYSIWYG" editors, such as FrontPage and Dreamweaver. I had more coding experiance as a beginner.
It is laughable to validate their pages, and find that they got 20+ errors, I'm even familiar with a page with over 100 errors.
Not mentioning any names, its hard to understand how those companies can stay in business.
Of cause all of these errors ain't really fetal, but you should always aim for some validity. If for nothing else, to ensure that the page will work in the future.
Choosing a Company
Don't trust anyone, and don't choose a company who's own website'(s) ain't validating towards the Doctype they are using.
There is an exception to this, because some errors might be intended. Most sites will have a few intended errors, but its important that they have included a Doctype.
Do not under any circumstances chose a company who neglects The Importance of Doctypes, the validator will generally tell you if it didn't find a doctype declaration. You can validate pages using The W3C Markup Validation Service