Originally Posted by
laxmillenial
The gate agent announced "This is new plane and it holds considerably less overhead bags than our older planes, so if you're in group 4/5 I would really appreciate if you all came up to check your bags proactively..."
Is this just due to the higher passenger density in coach? Or are the bins smaller?
It's not the bins. Density in Y may make overhead space tougher than in other UA widebodies.
But the other thing to remember is that GAs routinely lie about the availability of overhead space. Gate checking makes boarding quicker, even though it may not be necessary.