Is your position that it should be mandated by law or just the right thing for a business to do at their discretion? I grew up in an area where Canadian curren

Is your position that it should be mandated by law or just the right thing for a business to do at their discretion? I grew up in an area where Canadian currency often made it into the money supply and most vendors would just accept Canadian quarters at the US rate without a fuss. I remember the weird looks I got the first time I tried to do the same in a state further south. I feel like both are reasonable approaches but I would hesitate to legally mandate one approach because they are context dependent.