Most schools don't have blackboards nowadays, they have whiteboards or, if they're lucky, interactive whiteboards - and nobody objects to that.
Someone who once worked in our team interrupted me in mid conversation to tell me she objected to me calling my husband 'my husband'.
"What's wrong with that? We're married" I replied.
"You should call him your partner, not your husband. It's offensive to people without husbands".
"But, what if I said to you, you can't call your girlfriend (she was lesbian) 'your partner', you've got to call her 'your husband'. How would you feel?"
"She's not my husband" she spluttered "That would be very offensive to me".
"So why are you saying I can't call him my husband then? You call your partner what you want and I'll call my husband what I want and we're both happy. Right?"
"But I don't buy into the male-dominated, heterosexual marriage trap" She insisted.
Where do you go from there? She just could not see that my choices were as freely made as hers.