I sort of agree with Elrosh too. It can be very annoying for someone with 0 games to come in and upset a team balance by not knowing what they are doing. The flip side of this is you cannot rule out them being a smurf with a new account...
Here is an example of a game where a newb noob almost killed our team from their lack of understanding. This is a classic of why the pros fear the newbs!!!!
HowThe and I hooked up with Duke Greg (who ended up going 2v1 with his side of the maps opponents, but getting a feed from How who went econ from a bad starting position) and a newb. HowThe was in the pocket and the newb (yellow) was on the outside closest to the enemy (basically we were in 1/2 circles with the teams facing each other). I expanded rapidly towards the opposition and my ally (yellow), but lacked a big fleet due to the planet colonising and getting some higher level units like fighters and overseers. The opposition player (red) was getting supported by his feeder and spammed carriers. HowThe also joined up his fleet with me and we attacked red. Our ally (yellow) played like it was his first ever game (not MP game. First ever game of Sins period...) and did not attack red - instead went off colonising dead roids etc... and not getting civilian infra to prevent the -ve income. This lack of threat to red allowed him to focus on me and HowThe, spam more carriers and get support (HCs) from his feeder's fleet. The only reason our team won was by getting the yellow guy to quit and let the AI take over. HowThe was then able to feed the AI and get him to attack red's factory planet.
Now - looking at the replay of the game - the OP didn't fear us. They were aware of how the game was unfolding and therefore who they would end up fighting. They were actually winning until 1) HowThe and I managed to grind down the fighter spam some and (most importantly) 2) we convinved yellow to quit and let the AI take over. As previously stated, a bit of a feed from How and yellow had fixed up its negative income issues and was building a fleet (finally). We finally got the break we needed when one of the opposition (red) fled the grav well they were fighting in with their ally against HowThe and me (both with Lvl6+ eggs and How was putting some PJI in place) to defend against yellow. The other guy promptly accuded him of killing him and quit (which is true - we were able to phase inhib bomb his fleet and keep it there with the PJI. Plus I had some overseers and subs. So his HC were locked down with no air cover to kill the subs and the overseers kept both fleets alive from the HCs that weren't subverted. The AI that took over when he quit couldn't do anything either. Red then promptly quit when he realised we had killed his ally and could break out in two directions plus having the yellow AI do stuff to help us.
The following lessons can be learnt from this game:
1) Pros can still be beaten by teamwork. We were losing. It requires you to co-operate with each other and play smart.
2) Pros cannot always make up for a bad ally. 4 decent players vs 2 pro, and 1 total noob and 1 decent player will win as the newb will be out quickly and then the pro (who might be winning against the decent player) will be 2v1.
3) Pros are less likely to quit on each other as they know each other and stick it out to help their friends. This is the big difference I have noticed. A hurting pro can still be more lethal then a replacement AI.
4) You don't need to "win" your battle to help your team win. You just need to not lose it. Duke Greg has getting hit 2v1 but held (with a feed). While he couldn't progress much, he stopped them progressing, giving us time to work the other side of the map and hook into the back field.