Blocking doesn't always work, especially if you game on consoles. Moreover, it can even lead into stupid situations in which your recently met mate is destroyed by the ship you don't see.
As for PVP in Open... that's a very risky subject. On one hand, no rules is tempting. But then, if you feel that you cannot really cope in risks in open, find group of people on INARA.cz in the similiar timezone and timetable of gaming, nowadays Squadrons even, then play in Private Group only.
Myself, I cannot fully speak of Open Mode, because as Xbox One player I only had very mixed experiences. However, I can say that the only problem with Open Mode is... players themselves. Both ignoring and looking at the gindy nature of the game - especially with Engineers that lift up already steep PVP curve - there is no clean solution.
Yet I think the most important problem of Open Mode, because it is issue of players, is the fact every player goes on in his or her own pace. Some players spend hours in game and progress fast, but then there are people who are progressing very slow.
Some say "yeah, they should stick to Private Groups or Solo", and that's kind of solution... however, they miss part of the game that is meeting random helpful people. The downside is they can also meet players who prey on the weak - whatever their reasons could be.
