That's very true. I think IJROBP is sort of fortunate in this one respect because not many people would risk publishing unethical work in a journal that is so carefully reviewed and then closely read by a very qualified and knowledgeable readership that is so highly tuned in.
Just look at our letters to the editor! I mean, wow, the level of passion there is just incredible.
I suspect fraud detection is a more serious challenge for smaller, less read, less resourced, less well curated, and perhaps open access journals - which as stated by CWombat often operate under a high pressure for speed.