Only if you’re carrying something with a max. footprint of around 40 x 50cm, otherwise it’s resting on the rack or fork top cap and not being suspended anyway.
Agree on the sides of rack, don't think the top cap really causes that problem. Most sensitive thing I tend to carry is a max 12 bottles of wine or a corporate food order which the inner tube suspension really seems to help. Less worried about 4 boxes of legal filing.
Inner tubes are far better suspension for the stuff you're carrying, I'd take the weight penalty