Whis is a "weak geometry" and reason to cancel customer's order and turn off model from shop? REALLY? Guide says it can be >1mm thick How fat should I make this antenna? 10mm maybe? Pffff...
Its because the <2mm spire is significantly taller than wide. It is VERY liable to bend or break during the handling and packing stages. Shapeways is unable to determine HOW prints are intended to be used so ANY damage during the process is not acceptable, even if the end user would be fine with it. Why dont you remove the antenna and add a hole for it to slot into. Then you can sprue the antenna in a safer location for the end user to clip off and insert themselves?
I have to do that with more than 10 turret models then and afraid to imagine what would happen to all tank barrels on a smaller models