Incorrect. They can roll it. Same for 1,1,2 (at the end of combo...1,1,2 pushes them too far anyways)
Did some tinkering with trait just now, and while there are some set ups, the randomness makes it complete shit and not worth it. A raw b3 (teched or not) and raw 1,1,2 can lead to unblockable setups...however, if any other trait comes out it gets punished to oblivion. The "safest" way to land a trait is to f2,3 combo ender, and even then it is punishable by fullscreen supers and specials. On top of that, if you get damage buff trait, you are now left at fullscreen needing to get in while the buff timer just ticks away, effectively making it worthless.
All-in-all, there is no good way to get a trait aside from mindfucking your opponent into not reacting to it. The risk vs reward is absolutely not worth it.