In my experience, they certainly can. They won't do it quite like that, but there are many many ways they can make sure your child leaves if they really don't want them.
I speak as someone this has happened to this year. My five year old, diagnosed, statemented DS who everybody said would be fine in mainstream and who has no learning difficulties, only social ones, was bullied and pressured by teachers, the senco and the head until he had a breakdown and gave them a reason to permanently exclude him.
We have been forced down the route of a special school, and though I am very happy with the place we have and I know DS will thrive there, I am extremely unhappy that the choice was removed. From what I've learned from people on here and other local parents, this isn't unusual at all.
Schools can be very very underhanded. They will lie and obfuscate and trip you up at every turn if they feel it is to their advantage. Get an advocate if you can, someone who knows the system and what they can and can't do. It's very easy to get tripped up if you trust anyone in this process.
Oh dear, what a bitter old harridan I am! Very sorry xxx