I am used to the SI symbols, and wondered if it would cause confusion as well. However, I just noticed the other day that reddit tips are displayed in mBTC or uBTC (depending on amount and/or exchange rate, I'm not exactly sure).
Thats an issue imho. I mean the fact that some people use mbtc while others use btc. That adds more confusion to newcomers. We need to decide as community to either use one or the other.