- The default client should not contain limits that prevent running other versions / clients. If the default client won't distribute transactions with a fee less than 0.01, it's going to be very hard to run a client that allows a minimum fee of 0.001.
Shockingly... people are already doing that which you describe as "very hard" simply by upgrading.
Re-read the part of my post about people voting with their downloads. Then re-read the other post about transaction fees already changing. Then read the thread on transaction fees changing to 0.0005. And maybe study how mining works, too.