Regarding your friends comment about ' just injecting some extra insulin' -
I work in an open plan office with about 80 other people. 4 of us are diabetics, 2 type 1 and 2 type 2. Interestingly, whenever there are cakes in the office, the type 1s trough in. One of them piled a paper plate with 6 cakes last Thursday, and he was talking about how many extra insulin units he would need. The other type 1 agreed and they compared notes on their insulin pumps.
At the same time I chose a nut filled, fruit free flapjack, and the other type 2 picked a buttered scone (so that the butter would lower the GL). I saved mine until lunch, to try and bury the carbs under protein...
It is NOT my intention to criticise type 1s! I am simply suggesting that if your friend had witnessed someone eating cake and the dosing after, they wouldn't see anything wrong with suggesting you do the same.