Problem 1: If an indie joins in with a situation that involves multiple official ships, its sadly going to happen this way since the officials will probably all know eachother, and thus will be likley to talk to eachother more.
Problem 2: Depressingly , In the vast majority of cases ( Not all, I'll admit) adding an unknown indie to the situation just leads to bad things. Examples are: Adding to Gank Situations (indie joins already unbalanced fight), ignoring orders ("Everyone target ShipX", "let ShipY go, its pulling out"), and of course distresingly bad RP ("engagguinng ennmy ships") . All of that leads to a general feeling of discontent towards involving indies.
Now, as I said, P2 doesnt apply to all.
If an indie actually took the time to ask me about joining a situation, that would be a good sign that they were a good indie, and one that would be quite fine to have around and join in. I would not ignore them, unless for example I was engaged and couldnt type.
If I was asked to join a situation by an indie, I would not just ignore it, but I would take a very careful look at the balance of any fight. No-one likes to be ganked (stupid word I know).
Former leader of AFA (Farmers Alliance)
Former leader of [ALG] faction
Former GMG Trade Director
Retired due to career focus. Returned due to career de-focus.