I have been quite startled by the people starring messages in the chat without a proper reason and they just remove it a minute later. I want to suggest a mechanism: When actually 2 or 3 (2 makes more sense) people starred a message may it get to the "Starred messages" on the right of the chat. I think it is better.
I don't really thing this is a problem? Often times it's just people missing the reply button and hitting the star instead. No real reason to be startled or concerned.
More of a general response based on other answers.
It's chat, it's an even lower form of comments on the site. Creating a staring rule is like creating a rule about when you can and can not vote for something, or how to even vote on something. First, like voting it's all anonymous - so any rules that are created are non-enforceable. Secondly, moderators have the ability to remove stars, and frequently when I'm in chat I'll de-star noise. But starred messages are fun, it's just another part of the chat system and they're eventually sorted by most recent with more stars being favored. So it's not just a random cycle of text, stuff that actually has merit tends to rise to the top.
More to the point, I took a screen shot of the stars in chat.
I really don't see an issue with any of these.
I agree. I think people often star things in chat to point or agree, but un-star it because it probably doesn't belong on the starred wall.
It may or may not be "just for fun" although I have seen playful scripts that "vertical marquee star and unstar".
I'm not sure there's a really good solution beyond agreeing on what starring behavior is/should be.
Maybe implement a "Star Abuse System" that would check for a number of Star/unstar events. possibly 3-5 sets on the same post, or that many star/unstar events within a time period, say for example 5 diffrent star/unstar events within 5 min.
I can see the use for undoing them by accident, or even for a temp highlight, but without wanting it on the wall.
This would prevent the rapid star/unstar behavior, but keep it for the "accidental" or other use.
In trying it out, I see that there is a timeout on how long you can retract a star, so it is at best fun for a few minuets.
Even then seemingly random stars get people to look back and read the conversation to see what was funny, so I am not convinced that "hiding" one star messages off the wall would be good.