As I pointed out earlier, I don't want to lead someone down the wrong path, and would strongly recommend that if someone is interested in doing so, they research it thoroughly, but I remember reading in a trusted magazine or book (Gun Digest, one of the reloading books or something similar) that they tried using a test barrel and a piece of tube mag under it, and they were never able to get the rounds in the tube mag to detonate. Again, I don't recommend anyone try this without confirming what I SEEM to remember, but you have to keep in mind that the 30-30 is not a hard-kicking rifle and the shells in the tube are cushioned by a spring. Personally, I would have no fear loading pointed soft point bullets in a 30-30. Not sure I'd go with hard-jacket hollow-points, though, but then I would have no need of such ammo in a 30-30. Again, this is my personal opinion, and I have done some crazy things in my life. However, I would not class this as one of them.
BTW, has anyone ever run into proof that this is dangerous? I did a quick search using Google and wasn't able to find anything that either proved or disproved it. A lot of warnings, but no actual cases.