Whilst I agree that 10% is probably not going to be enough to make a huge dent if the percentage starts to get a lot more than that (i.e. approaching 25-30%) and the block size has managed to vastly increase in size (as many supporters of BU seemingly are fine with) then this scenario does end up becoming a possibility.

In short a "fee market" needs to exist in order to ensure that a large enough number of different mining operations continue to confirm transactions.

Also the fact that a shit-load of non-fee paying txs (or too low fee paying) are flooding the network at the moment (as has happened a few times before) is perhaps proof that those wanting to do exactly what the @OP fears they are trying to do are pushing hard at that (by trying to convince people that we need much bigger blocks).