Well horizons might not behave exactly the same (this is all theoretical physics) but there is quite a long chain of papers arguing that Hawking radiation arises from all sorts of causal horizons, and for the same sorts of reasons that motivate it for black hole horizons. See Gibbons-Hawking effect or look up "de Sitter radiation" on Google scholar. Here's just one paper.

With regard to your edit, the paper by Bousso et al does in fact discuss physical interpretations of the "end of time" effect, and scrambling into radiation appears to be the authors' preferred interpretation. See Section 5.3 on "causal patch measure" and this paragraph:

We now see that there is a different, more satisfying interpretation: the inside observer is thermalized at the horizon. This interpretation invokes a relatively conventional physical process to explain why the inside observer ceases to exist. Time does not stop, but rather, the observer is thermalized. His degrees of freedom are merged with those already existing at the boundary of the causal patch, the horizon.