Thanks for the knowledge, I don't knew that miners can control the min fee to "mine" and others few things...
About the wallet, for example online wallets like blockchain.info, they can control the fee amount to 'help' miners?
it's not a fixed or default fee, You can reduce/increase it but they recommend a certain amount to get a confirmation, I guess it's free to use any fees you want and it would depend on how busy the network is, Most miners are composed of thousands of users therefore miners would need to pay those to set a fee and even then people won't be forced to use it.