But that has a little advantage. When they send you used items, it is easy to notice.

If you buy at some reputable shops, they know how to scam you and resell used items as brand new, not as refurbished, grade A or whatever, which is illegal at least in EU.

For example, I wrote to the customer service of a famous fountain pen shop in the UK asking about return policies on a very particular model which comes sealed with stickers. I was shocked when they said I could not only open the box and inspect the pen, but also ink it and use it. If after a week I decide I no longer like it, I should just send it back. It will get sold as brand new. They only advised me to open the stickers really carefully to facilitate their (scam) task.

In fact, if you shop around their website, you'd notice there are practically no refurbished or open box items in proportion to their high volume of sales.

If you ask any fountain pen enthusiast, a pen that has been used for a week is not new. Just like a car that has 2000 km in the dial. Good shops even sell models have been dipped in ink, not even filled, at a heavy discount.

For example, no Pilot is sealed except the 823. I don't think any brands other than MB, TWSBI and Dupont make it obvious to notice if a pen has been opened.

Same with good mechanical keyboards. E.g. all Leopolds are sent to EU and US retailers without stickers.

Trading Standards used to be really great about responding to these sorts of complaints, and for larger sites and retailers they'd have their own test shopping as well. Tory austerity means they haven't had budget for years so are almost completely toothless. Only when Brexit stops being the only issue driving UK politics will the systemic destruction of the successful parts of the UK ever get noticed again.