said by yock :

This seems like the wrong solution to me. Why not simply recommend through your documentation that users use serif fonts?

said by Steve :

Which would you rather provide tech support for:

a) forgotten-password link that avoids troublesome characters
b) "How do I change the fonts in my UnknownMail client?"

Corollary to (b): wanna teach my grandmother to change fonts on her browser?

said by nixen :

Two possibilities: 1) set your display page's FONT attributes to instruct the user's browser to render a Serif-based font; and/or, 2) put instructions in to use cut-n-paste to load the temporary password into the client's connect info.

said by Steve :

The former is not universally reliable, and the latter is just more stuff to support.

said by Steve :

Friedl's rule: the best tech support is that which is not necessary

In 1960, DEC engineers realized that in specifying connectors on a frame, where numbers mark the card slot locations and letters mark the connectors on individual cards, some letters cause confusion. Thus the letters G, I, O, and Q were dropped to avoid confusion with C, 1, and 0. The remaining 22 letters were since known as the DEC alphabet[citation needed].