Do care/content labels have to be visible and permanent at the point of sale? 

Yes. Except in special circumstances, care labels must be permanently attached to the apparel and legible throughout the entire lifespan of the product in the U.S., EU, and Canada. Consumers may, however, choose to remove tags after purchased. 

Footwear is exempt from this rule.  

For more information, please visit the FTC's website on labeling, Canada’s Textile Labelling Requirements, and the EU’s Guide on Textile Labels