I think that in version 3 I was allowed to run 'lb init' as normal user. On version 4 I get this:
$ lb init
E: need root privileges
$ apt-cache policy live-build
live-build:
Installed: 4.0~alpha37-1
Candidate: 4.0~alpha37-1
Version table:
*** 4.0~alpha37-1 0
100 /var/lib/dpkg/status