Not all ultra vires challenges based on legality review raise exceptional constitutional considerations warranting the application of Biowatch costs principles. For Biowatch to apply in a costs appeal, there must be genuine and substantive constitutional issues at stake, which normally requires the vindication of a specific fundamental right protected by the Bill of Rights. While legality review is inherently constitutional in nature, it does not automatically entitle litigants to favorable costs treatment where no fundamental right is sought to be vindicated. The fact that litigation involves statutory interpretation or administrative law challenges, even though such interpretation must be done constitutionally, does not without more establish exceptional circumstances justifying an appeal on costs only. Courts retain discretion to distinguish between different phases of litigation: forcing organs of state to discharge constitutional obligations may raise exceptional circumstances, while challenging the content of resultant regulations on purely legality grounds may not.