Graber bike rack installation on Honda Accord I have Graber 2 bike rack. 
While installing I noted top narrow side of Graber arm rest on top of the trunk and bottom wide arm rest on rear bumper.

How safe it is to carry bikes like this ?
If Bumper strong enough to hold 2 bike weight ?
Note that car is 17 years old.

Thank you,
V
When properly installed these type of trunk mounted racks do not actually rest on the bumper. 

The lower arm should be positioned slightly above the bumper and bottom edge of the vertical part of the trunk lid. The weight of the rack and bikes is actually supported by the top straps. 

See the pictures at the Graber web site (not sure if it's exactly the same product, but it shows proper installation.)

https://www.graberproducts.com/product/guardian-elite-2