In the case of a hyphotetical situation of a realm containing 20 nobles and 8 new nobles arrive, all from the same old realm. Then I would say take them in, but don't trust them at all.
It crushes any stability in politics, especially if you would have a election with each noble having equal votes. Thats 40% extra votes available. Old nobles will look at the newcomers, but thats just my oppinion, with great distrust. These 8 refugees could suddenly be, if they would stick together, a political force on there own. I would find it very strange if they would be accepted in a realm without any struggle.
one or two refugees are much easier, as they are less of a threath to the political situation of a realm.
