Sordid will probably respond as well but here are my impressions:
1. The cap is as valid a target for us as anything else. (Most of us are suicidal, or at least don't care about dying). So either we attack the cap (esp. if we roll beserk) or if we don't then we'll likely just float silently by. I for one am not going to pirate someone in front of a cap ship.
The only time I could see this being an issue is if there was a liner/(ship carrying people) and a cap ship. In-RP I'd go for the liner, easier prey and lots of it, and the cap ship couldn't shoot me without also hitting the transport once I was entangled with the liner. OORP, being aware of the rule, I'll attack the cap ship first or try to quickly arrange something with in-game PMs if there's a positive response (Eg. I'll board and the capship can RP sending forces over to assist. At which point if it's just me a whole bunch of Marauders likely get blasted).
2. It's like any other thing written into the chat line. I've been blown away serving an engagement notice before I moved once. It happens and it's frustrating, but meh. If someone can kill me in the time it takes me to write "/dice," I'm not going to win anyway.
Also, if someone opens up on us then it's fair game for us to shoot back. If we win, it's BBQ marauder-style.