This is absolutely the only way such a feature could be sanely realized, and it would require so many invasive changes it is absurd.

Off the top of my head you would need to patch glibc, all the major shells, probably half of coreutils, anything that daemonizes similar to nohup (including screen and tmux, god knows how many CPAN modules), ...

Perhaps you could do it like the bash command time, whose output is a bit hard to capture...

GNU source is never a pleasure to read, but as far as I can tell the bash builtin "times" prints to stdout.

This can be observed by running:

  bash -c 'times whoami' > /dev/null