AbstractTokenContract allows arbitrary command

[LHao87]

In the AbstractTokenContract, transaction verification functions are called in the following order:
verify() -> dispatchOnCommand() -> verifyIssue(), verifyMove(), or verifyRedeem()
In the function of dispatchOnCommand(), it assumes the command is one of IssueTokenCommand, MoveTokenCommand and RedeemTokenCommand

when (commands.first().value) {
	//verify the type jar presence and correctness
	// Issuances should only contain one issue command.
	is IssueTokenCommand -> verifyIssue(commands.single(), inputs, outputs, attachments, references)
	// Moves may contain more than one move command.
	is MoveTokenCommand -> verifyMove(commands, inputs, outputs, attachments, references)
	// Redeems must only contain one redeem command.
	is RedeemTokenCommand -> verifyRedeem(commands.single(), inputs, outputs, attachments, references)
}

If someone makes a new command, and use it with the FungibleTokenContract, then the contract will verify nothing since it does not know the command.
Shouldn't the above code throw exception at the end when the command is unknown?