I did some reading on this and it seems like Denny said that many have pointed the finger at WL before. Bells and Founders I guess had issues that traced back to WL.
I see WL also has this disclaimer on the Yeastman site before purchase, bold added by me.
Terms and Conditions: While we strive to produce the best products possible, yeast and bacteria are living, microbiological products that are subject to environmental conditions, for example, during shipping and storage/use at the customer. Therefore, the total liability of White Labs to customers shall in no circumstances exceed the sum of the purchase price of products from White Labs. White Labs is not responsible for other ingredient costs, sales costs, labor, etc., but we stand behind our product and our promise to you is that each batch is rigorously tested before it is released to you. While we do our best to plan, schedule, and ensure that we have sufficient stock on all of our strains and every order ships complete, on some occasions we may run out of stock due to a number of factors including high demand, low concentration on cultures, and QC-related issues.