There is no legitimate justification to infringe on a contract between a willing buyer and a willing seller, but to actually fight these crackdowns you have to spend lots of $$$ on local political campaigns in every municipality. Easier said than done. Unless that massive lobbying investment (or at least a publicity campaign, like SOPA boycotts) happen the entrenched interests win by default and lots of peer-to-peer transactions will move to gray/black market.
Prohibition always creates speakeasies and the organized crime to protect them.
EDIT: To address "devil advocates", yes, most regulation mandated and enforced by government is a terrible imposition. Self-regulation that preserves consumer choice is a much better idea. You want to pay extra $$$ for a better level of service / protection /etc? Make it an optional line item with explicit cost.