You can only reinforce a character if it has the defender characteristic, correct?

Using the game effect (exhausting an adjacent support row character of the same affiliation) can only be done to a defender, but effects such as Burn Rubber can be done anytime unless it specifies "defender".

That's what I was wondering. I didn't know if Burn Rubber needed errated or if it broke the rule.

It doesn't break any rule. You can only "reinforce" a character (exhausting the support row character...etc.) if it is a defender. You can give any character the "reinforced" characteristic, however, thru another effect.