Does adding ™ help or hurt?

[measurableROI]

I have a client who rents kids' party products that are branded (Batman, Curious George, etc.)  Does it help or hurt to put the superscript "TM" in the Meta Title, or other meta or actual content of their product listings?  I have some guesses, but am curious for other opinions / data!  Thanks very much!

[Debdulal]

_It is perfectly normal to use - &trade and I do not think that it will make any impact on the visibility whatsoever. _