Why only the trademark holder has to use the TM symbol with their product names (and only if they want to), and how enforcing a non-rule to the contrary might make you look ignorant of intellectual property laws, or worse. Today, on the Canadian, Eh? column at Copyediting.com.
The R symbol follows the same rules, since R means “registered trademark” and TM means simply “trademark.” You don’t need to use either in your writing.
Photo by Simon Bleasdale used under CC BY-ND 2.0 license.