You're probably right if you do professional runs. This is the few-bucks mass-production who-cares-its-cheap-as-borscht-anyway process we're talking about; it usually comes with 50% e-testing and I actually have a panelized PCB with traces very close to the minimum come back with a few of the PCBs crossed out. The question then becomes: what about the traces that just made it? Can I run any current through it, will they deteriorate over time? Hence my choice to (advise to) beef up the traces a bit.