Is there a way to tell whether you will be able to access a POCO other than attempting to launch planetary materials to it?
I discovered the hard way that the russian corp who owns a POCO on some planets that I am doing PI on has denied public permissions to access their offices and I seemingly have no way to get the materials off planet.
I don’t know if there is a way to know if public access is blocked or not but you can always launch materials from your command center to bypass the POCO.
If I recall, when you access a POCO that you’re not allowed to use, the tax rate shown in the upper left hand corner will show 0%. Of course, if your actual tax rate is 0%, then I don’t know what the tell is. Feel free to experiment and report back because I’m not seeing a definitive answer to this.
You might try writing the owner of the poco a nice message and use Google translate to get it in their language. You might be able to convince them to give you access with a reasonable tax.