The "Angela" one specifically started not as a "use this codeword in any bar", but "in our bar, staff is trained to react to this code word" posted in the women's restrooms at a bar.

These are used with varying degrees of regularity in different situations.

"Mayday", "SOS", "Securitay", and "Pan pan pan" in aviation and boating. For aviation also 7500, 7600, and 7700.

A list of codes used in hospitals, including combative individuals, armed confrontations, bomb threats and the like:

https://www.calhospitalprepare.org/sites/main/files/file-att...

For lists of codes used in other contexts (police, subways, ships, air travel: https://www.theclever.com/15-secret-emergency-codes-youre-no...

Note that without specific training and regular drilling, these are likely to not be especially useful. For communicating to the public a plausible-but-clear explanation, e.g., "police investigation" (usually code for suicide, possibly other death) is used especially in transportation systems. A "police investigation" on a transit line or bridge is frequently a suicide or attempt.

I've seen a video posted online of someone ringing the emergency services "ordering a pizza". It was a pretty emotional watch actually because there was no description so it took the viewer longer to realise what was going down than the operator. Really hit home just how hard their job is.

Have worked in bars and can confirm no one is going to recognize the Angela thing without additional context. It's just a feel-good memey thing.

They stop working once everyone knows about them. If your attacker knows your codeword it stops being a codeword