Sometimes I need to alter various strings related to math objects for feedback messages. My current example is that I'm using parserAssignment, and for this seed the answer is "B=0". Since "B" is the variable and since the default cmp_class is a little intimidating to intro algebra students, I use

cmp_class=>"an equation of the form B = ___"

or actually,cmp_class=>"an equation of the form $var = ___"

This should show up in feedback messages like

"Your answer isn't an equation of the form B = ___"

However it shows up as "Your answer isn't an equation of the form b = ___"

Which makes me think that strings for these math object keys are automatically made lowercase. Testing with other uppercase letters confirms this. Is there a way to prevent this?