This is one of the situations where SST doesn't inherently prevent operator error. The other major one is the possibility to have data for male and female athletes in the same file, and to potentially send timing data to the wrong gender. Both situations can be avoided by establishing 'safe work practices', like the one posted above. I have a pre- and post-race checklist that includes the same practice of switching off live data transmission from the B timer. It also includes saving the B timer file after first and second run in case those data are needed later.
Other software platforms have different approaches, building in the structure to remove these possible situations altogether. In dTris, for example, males and females must be in separate files. If you're using Vola or dTris, live timing publishing software isn't part of the timing software but instead it runs on a separate computer networked to the A timer. The B timer data simply can't make it to the live timing site.
Some view this possibility for pilot error as a weakness of Split Second. But the potential areas of concern are well understood and can be handled by simple operating procedures. There is a gain in versatility and simplicity as a result. It's nice to have timing and live publishing integrated in one package, and the software fees include web hosting.