Public institutions must avoid even the appearance of impropriety when selling art.

It told him to take steps "to guard against even the appearance of impropriety."

Rather, there is an appearance of impropriety to some reasonable people.

"Going into that room gave a definite appearance of impropriety," he said.

Why not in the publisher's office, where there would be less appearance of impropriety?

"You can see how there might be at least an appearance of impropriety."

"Clearly, no one regrets more than I do the appearance of impropriety," he said.

This is often known as creating "an appearance of impropriety."

Then we started punishing them for the appearance of impropriety.

You do not wish to engage in the appearance of impropriety.