Additionnal system information : 
OS : OpenIndiana 151_a3
samba global configuration : abe="true", guestok="false" aclinherit="passthrough-x", aclmode="passtrough"

When using rsync without any the following flags : --perms, --executability, --chmod, the default zfs ACLs are not applied.

here is an example :

I have a directory with the following acls : 

drwxr-xr-x+181 shamu    staff        225 May 20 01:24 Folder
             user:shamu:rwxpdDaARWcCos:fd-----:allow
              everyone@:r-x---a-R-c---:fd-----:allow

When I create or copy a regular file to this folder, the new file's alcs look like this :

-rw-r--r--+  1 shamu    staff          0 May 20 01:30 file
             user:shamu:rw-pdDaARWcCos:------I:allow
              everyone@:r-----a-R-c---:------I:allow

We can see that the ACLs have been correctly inherited from the folder.

When I rsync a file to this folder, the acls look like this : 

-rw-------   1 shamu    staff    11010048 May 20 01:49 file
                 owner@:rw-p--aARWcCos:-------:allow
                 group@:------a-R-c--s:-------:allow
              everyone@:------a-R-c--s:-------:allow

from the manual : 

"... when --perms and --executability  are  both  disabled,  rsync's  behavior  is the same as that of other file-copy utilities, such as cp(1) and tar(1)."

I read somewhere that full solaris/zfs acls support should be for 3.2.0 but I'm wondering why those acls are being set by rsync 3.0.9