The gray area is a matter of scale and purpose. If you have a small business which serves as specific market it's a good idea to make the site as user and disability friendly as possible. If, however, your market serves segments with a likeliness to have various handicaps or disabilities you should address that with an ADA Compliance review of the site. Also consider the scale and purpose of an organization. Publicly traded large businesses need to concern themselves more than a single location family owned retailer and if someone sues your flower shop because the text was too small or didn't have "image alt tags" causing them distress... That's pretty frivolous and would likely not stand. 

Now you know that some types of content and format on webpages can pose barriers for people with disabilities. The next steps are to develop an action plan to fix web content that is currently inaccessible and implement procedures to ensure that all new and modified web content is accessible. The website accessibility checklist included in this section helps you assess what needs to be done.
ADA Compliance is not exactly new, but there is a noticeable increase in lawsuits. but the most important thing you can do to be ADA compliant is to make your website accessible to people with sensory disabilities like deafness or blindness. This includes alternate text for images and media that are more than decoration, like infographics and photos of things that explain or pertain to website content. This is most important if your website represents a public physical location, like a hotel or store of some kind. Because these lawsuits are usually pursued in the necessity, where people with disabilities really need access to such a business and can't obtain it.
Most recently, however, pizza chain Domino's has been brought under suit for their website not being accessible for specialty ordering. The U.S. Supreme Court refused to review the case, instead upholding the decision of the 9th U.S. Circuit Court of Appeals who said the “alleged inaccessibility of Domino’s website and app impedes access to the goods and services of its physical pizza franchises—which are places of public accommodation.”
While the influx of the world eliminated the need for brick-and-mortar locations for all stores (think eBay or Amazon), all of the above categories typically had a headquarters, if not multiple locations where one could visit and interact.  This would ensure a unique experience, often depending on the individual needs of the visitor. For instance, when visiting a municipal building or institute of learning, a variety of methods are available to get to higher floors (stairs, elevators, ramps and escalators).

The words in the tag should be more than a description. They should provide a text equivalent of the image. In other words, the tag should include the same meaningful information that other users obtain by looking at the image. In the example of the mayor’s picture, adding an “alt” tag with the words “Photograph of Mayor Jane Smith” provides a meaningful description.