I wonder if that rule is more to avoid people doing lazy ports of existing artwork files leaving stuff like "X Disc Box Set", "Our Price[1] Exclusive" or the Compact Disc logo on the covers. Although it's hard to parse, so I might be wrong.

"No Dates" is funnier, plenty of compilation albums and so on must break that, plus stuff like Prince's 1999. Not sure what that's really meant to catch.

[1] Other record stores are available, and they may even still be in business.

Are they gonna take Kanye's Yeezus or Jesus is King off of the service? Oh right, these rules only apply to small artists.