Tested this today with SNAPSHOT-7-6-5. I can confirm that waitForChild now has an effect however it's not the effect I was personally hoping it would have. Essentially I wanted it to have the same effect as setting <daemon>true</daemon has when running jetty:run, in that Jetty would start (in a new JVM) and Maven would block until Jetty had started, at which point Maven would continue (in my case running the integration test phase as I have bound run-forked to the pre-integration-test) running the requested goals. What is actually happening is that the forked JVM begins to start but control returns immediately to the parent process which executes my integration tests, these all fail with connection refused errors because Jetty hasn't yet completely started up.
Is there any way to make jetty:run-forked behave more like jetty:run in terms of blocking? I realise that there may be extra difficulties in terms of inter-jvm-communication but this would be great for cases like mine where we need a fresh JVM but want to support running Jetty for integration tests.
I seem to be unable to re-open JIRA but wanted to comment my findings.