Based on what I read the safety is that the process happens in the dev branch not master. Essentially no harm is done as long as someone spots the problem within a reasonable time period:

for i = 1 to 180 days # 6 months of 30 days each, this is a magic for loop that knows when a day passes { 1. new PR gets eyeball review 2. PR is merged to dev branch 3. if merge == crap, new PR made to address crap, goto 1. elseif, goto 4 4. if i == 180, merge to master. elseif, goto 1 }

https://forum.getmonero.org/4/academic-and-technical/2556/c4-discussion

The system allows ample time for review but is not perfect. Backdoors are always possible and commits from new contributors should always be looked at carefully even as they are assumed to be trustworthy IMHO.

The goal is to be seen as welcoming to new contributors.