embede G2 jump back to standalone mode in mambo

I am using nightly build of G2 (5/10/05) with mambo 4.5.2. After I removed all group permission from the root album (only admin will have access), the embeded G2 will just jump to the standalone mode. I am using

apache 2.0.53
windows xp
http 4.3.11

After some debugging, it seems that embeded G2 may send output out directly or redirect the browser to other pages on error or some special conditions. This seems to be a very bad behavior in an embeded applicaiton. If G2 detects errors, it should return error code or related info to embeded application (mambo) and let it display approriate info.

The following code does not work well in an embeded environment.

if ($g2data['isDone']) {
exit; // G2 has already sent output (redirect or binary data)
}

Does G2 do redirect or send binary data in many places ? If it is only a few places, we can check if we are embeded and behave differently.