"CabinCrewe, wrong. Look it up"
Read my post again, particularly the word "should", as in my opinion.
"Before a PSO can be imposed, Regulation 2408/92 requires that the route must:
• be to a "peripheral region", or be to a "development region", or be a "thin route to any regional airport"
• be “vital to the economic development of the region"
• and require a PSO to ensure the "adequate" provision of scheduled air services – in assessing “adequacy”, including other forms of transport