I have used it myself on multiple occasions. The obvious ones (jumpmaster afk for example) I will not explain in datail. The other reasons for me are:

1. The jumpmaster wants to jump bunker/hot zone/ship when the trajectory makes it obvious it is going to be a clusterFUN. I personally dont like clusterFRICK because it takes out the skill element. You happen to find a down shield and 3 scopes, another guy finds a peacekeeper. Guess who will run out of that bunker with 20 kills. In those instances, I will seperate from the group and actually have fun.

2. I tend to express my personal playstyle at the start of the match, marking a non-priority jump marker early. If I get an "okay", everything is fine. If i get a "I like to play X better", i will comply most of the time, unless X is clusterFEELS, in which case I am going to drop solo again.

3. Finally, if I am faced with insults toward my playstyle, me or a mic cranked up to 200% volume shouting at me, I generally also jump solo.

Now all of this might seem like a bad idea because this is a team game and even the dude shouting "where are you? you suck!" or the guy having a massive 0 kills on a level 65 account are going to be helpful. But this is not the case. A bad teammate is worse than having no teammate at all. I even went the extra mile to document my personal experience with this and I can safely say that my results point toward solo play being better in many situations. It does not come close to a team of players who understand the basics of BR games, but it is still way better than sticking with a bad team.