If job control is not enabled, background jobs started with ... & ignore
SIGINT and SIGQUIT so that they are not affected by such signals that are
intended for the foreground job. However, this should not prevent
reassigning a different action for these signals (as if the shell invocation
inherited these signal actions from its parent).
Austin group issue #751
Example:
{ trap - INT; exec sleep 10; } & wait
A Ctrl+C should terminate the sleep command.