Ingame Penalty for no taking team's banners!

It depends. If it's unreasonable to grab a players banner and then they're voting you for not getting it. There are a tonne of independent variables around grabbing a banner.

If someone just being a * and doesn't grab it that's different.

For example last night crazy battle. Respawned teammate. Then we just helped him gather his stuff, we're pressed for time between side of market and ring, i scout ahead to see if we have a safe path, i notice enemies holding down cave entrance but we can go west towards bunker side instead.

I had already pinged enemies and briefly engaged, teammate 1 too. Realising this was going to be futile/disadvantaged, i pinged away from the battle west. (Ping marker wasnt misinterpretable for location).

So we go west. Teammate decided to rush and push cave on his own and gets wiped. Not about to go and get that banner. 

Stupid decision from teammate, ignored the squad, would seriously disadvantage us to attempt to get banner and disadvantaged now we're a man down.

We take a strong vantage point in the smaller ring, I knock gold shield and break other, teammate downed i revive and try fight the pressing 2.

We lose.

But we had no choice to get that banner. And it's as a result of that teammates ignorant actions.