I worked in a field that... had more than it's fair share of love/relationship scams across borders.
While I do appreciate the OP's sentiment and warning, I don't think it's a hard and fast rule, and the advice should be taken with a grain of salt.
Personally I find it a bit amusing because the data I was exposed to suggests for every 10 cases that were classified as a "scam", there were 20/25 other relationships that, weirdly enough, was legit and surprisingly, worked out better than domestic relationships.
Surprisingly though, the relationships that work out do not have the same media coverage compared to those that do not work out.
Personally I had to sift through a lot and the conversations were surprising to those clients I reached out to.
The sentiment seems to have been for those whose relationships were working, they were too busy living their lives and achieving their goals for their family that they didn't have extra time to focus on the noise. They had time for their families and partners, sure, they just chose not to let the outside influence their home bubble.
Not saying it CANT happen, not saying it WONT, just saying be careful.
For the record, haven't been and will never marry, just someone exposed to the data.