when you say that "would be questionable or inadvisable for a bank to accept such a check for credit to someone's account" you mean deposit account, correct?
That's correct. Suppose ABC Builders sends its accountant in with a check payable to the bank that's supposed to be for a tax deposit (TT&L payment). Instead, the accountant hands you the check with a deposit ticket to the accountant's own account! Don't think this hasn't happened. I've seen it close up and dirty. To the cumulative total of $300,000 before ABC Builders heard from the IRS about failure to deposit taxes. Guess who had to pay those taxes?
If a check is properly payable to the bank (for its own accounts), the normal proof department endorsement is probably fine. Often, departments have stamps they use to indicate they processed such checks so the bank knows what to do if one of them bounces.