In T 1448/09 the board held that the appellant was not at fault in failing to address, in its statement of grounds of appeal, a reason which, in the circumstances, could genuinely have been misunderstood. The principle of good faith required adverse decisions not to contain any ambiguity that could affect their comprehensibility.

The EPO is generally obliged to draw the party's attention to easily remediable deficiencies. However, the principle of good faith does not impose an obligation to warn a party of deficiencies within the area of the party's own responsibility (for more information, see in this chapter III.A.3.3.1).