This might be a dumb question to ask, but having just read the eligibility terms, I think I understand them and I wanted to ask.

I get that you have to be travelling on Star Alliance, from that airport. IE: I was travelling PTY-MEX (star) MEX-DFW (AA) DFW-YYZ (star) so at MEX I had no lounge access. That makes sense to me, I don't like it since I was on star before and after, but if that's the rule, then that's fine.

My question is this, I swear that people have posted about getting access when not travelling on star. Is that just good fortune? Show up to the lounge and ask nicely? Or are there lounges in the network where it doesn't matter who you're flying, you can access as long as you can prove you're star gold? If so, where are they?

It really depends on staff, mood, time of day, sympathy etc
I was able to get into S* lounge by kindly asking and stating that I am on an AB flight, unfortunately was not able to get any decent LH connection and would love if they could make an exception - which they did

if you have UA club or Maple leaf club membership, you can enter the lounges without worrying

Generally, if you have a paid membership to a lounge then you can enter those lounges regardless of flights. If your access is based on elite status, reciprocal privilege, or class of service, your access will be dependent on having qualifying air tickets for same day.

Obviously exceptions exist, but it's a general rule.

Fair enough, thanks for the responses. Makes priority pass sound almost worthwhile. I've paid $150 CAD in the past year on 3 separate 1-time entries to lounges where either a *G lounge wasn't present (MIA) or when I was on another airline.

I think the CCs that offer it are too pricey and I just can't justify the cost to myself up front. A better option for me is probably just sucking it up in those instances and hanging out in the terminal, but I'm so addicted to lounges now