Is it true that holding aggro 100% of the time isn't possible at low levels?

[Khalithar]

In a low level dungeon like a tam-tara, if you go in as a brand new leveling gld/mara and you have an ilevel capped brd or blm in the group, there's a good chance they will be tanking a large number of the enemies. Conversely, they'll tear through things at a very quick pace so it won't matter so much. Granted the same can be true of any really geared dps, but I've noticed blm/brd tend to pull off lowbie tanks most easily.