Actually, you picked exactly the wrong example of why legal tender laws don't matter. People are legally obligated to accept legal tender (even in ridiculous forms, such as a dump truck full of pennies) for the payment of debts (eg, taxes, mortgages, bills, etc) (however, non-legal tender may still be used to pay off debts if both parties agree to it).
That is a mismoner. No entity is required to accept legal tender in all forms (like for example a dump truck, or even any cash) they are just obligated to accept payment in some form of legal tender.
As an example, my mortgage is held by a non bank entity. They have no offices/locations open to the public and federal law prohibits mailing cash (in any form). My old method of satisfying the debt is by check draft, money order, cashiers check, ACH, or bank wire. That doesn't violate any legal tender statutes. Now if the "bank" demand payment in gold or chickens it would. However them placing restrictions of what forms of payment they will accept are not unlawful.
The purpose of legal tender laws is to ensure that a debtor holding legal tender has SOME mechanism to repay that debt not to obligate creditors to asinine restrictions (like requiring they accept a dump truck of pennies).
Now the legal tender laws in Canada may differ.
From the source (US Treasury)
I thought that United States currency was legal tender for all debts. Some businesses or governmental agencies say that they will only accept checks, money orders or credit cards as payment, and others will only accept currency notes in denominations of $20 or smaller. Isn't this illegal?
The pertinent portion of law that applies to your question is the Coinage Act of 1965, specifically Section 31 U.S.C. 5103, entitled "Legal tender," which states: "United States coins and currency (including Federal reserve notes and circulating notes of Federal reserve banks and national banks) are legal tender for all debts, public charges, taxes, and dues."
This statute means that all United States money as identified above are a valid and legal offer of payment for debts when tendered to a creditor. There is, however, no Federal statute mandating that a private business, a person or an organization must accept currency or coins as for payment for goods and/or services. Private businesses are free to develop their own policies on whether or not to accept cash unless there is a State law which says otherwise. For example, a bus line may prohibit payment of fares in pennies or dollar bills. In addition, movie theaters, convenience stores and gas stations may refuse to accept large denomination currency (usually notes above $20) as a matter of policy.
I picked that example on purpose.