In some part of Indonesia (mostly Java), "mari" is used as BYE. I don't say that all Indonesian use this kind of idiom as BYE. But in good Indonesian, means formal Indonesian as we refer to KBBI (The Great Dictionary of the Indonesian Language), "mari" is an interjection means : ayo (an interjection that ask you to come) as well as Hi!, "Ouch", "Oh" But it can also be used in a sentence, for example: Mari datang ke rumah saya. (more polite/formal) Ayo datang ke rumahku (less formal) In your case that "mari" is used to express "bye", I'm sure it's only used in some parts of Indonesia especially in Java. And I am sure, there are still some people in another part of Indonesia who are not familiar with "mari" as "bye" The most common expression is "daaahh" for "bye". I'm originally from Medan, North Sumatra. In Medan, we don't use "mari" as "bye". I barely hear it from people. When I moved to Central Java, then I heard a lot of this expression used as "bye".

Yes Pak Marcelo, it is quite common for Indonesian to say "mari" for good bye or to excuse themselves. Sometimes for simple we just say "yo"!

Usually for the 'adult men' to each other even 'the young' to 'the elder'

mari = ayo