So if the core devs change the minimum fee schedule, lowering the maximum "free" tx from 10,000 to 1,000 bytes - how will that not cause a hard fork? Or at least prevent nodes running old software from propagating a new Tx?
https://github.com/bitcoin/bitcoin/blob/master/src/main.cpp
I could be reading this wrong, but looks to me like the minimum fee schedule is part of the "standard tx" test, and so nodes with different fee schedules wouldn't be able to send all tx's between each other.