I spent 8 years working for UPS (changed careers a year ago), and i can tell you from personal experience that there are a ton of grow lights, hydro kits, nutrients, etc shipped all around the country every day without the cops paying any attention or trying to seize the packages along the way. In all those years I can only think of a couple of times that the police or DEA showed up at our hub (second largest in the country), and they weren't there for lights or other equipment.
Now, I can see the security risk or leaving a paper trail if the police are already suspicious about you, or if you do something that makes them suspicious, but if you don't have any reason to think they've ever heard of you and you're keep things low key it's not something I'd lose a ton of sleep over. If you're really that freaked out about it you can always contact the seller and make arrangements to pay them by money order-You'll just have to wait longer, since they won't ship your order until they get the money order.