Strange magtape anecdote

[Al Kossow]

http://mnembler.com/computers_mini_stories.html

"George Dragner always wore a belt with a metal dragon buckle.  He was a colorful character known for pissing off management.  His most 
famous act was tossing a chair through the window at a customer site. The customer refused to believe that the lack of humidity in the room 
was screwing up his magnetic tape media.  As the tape heads depend on the moisture from the air to prevent the magnetic oxide from being 
torn off the media from the friction during a rewind. George broke the window to prove his point.  He was right ! "

There is a minimum RH specified for tape, but "tape heads depend on the moisture from the air"  ??