Ruben,
To play it safe, we set this flag to "yes" by default. However you're right. It only really becomes an issue for panels with high aspect ratio. If you think this doesn't apply to you then you could set it to false. In fact, you may want to run the analytical methods instead. These run much faster and they handle curved panels now.
To activate the analytical buckling methods for curved panels, select the backdoor flag
Misc > "Curved Panels use Flat Panel Buckling" = Yes.
this flag needs to be renamed. It actually means that HyperSizer will use the analytical methods for curved panels. The analytical methods to handle curvature now.. so no additional conservatism.
I hope this is helpful.
-James