Is it safe to empty C:\ProgramData\Microsoft\DataMart\PaidWiFi\OffersCache\Offers\?

Anyone tried emptying

C:\ProgramData\Microsoft\DataMart\PaidWiFi\OffersCache\Offers\

The data contained within this location is only used if the Paid WiFi feature is enabled. Given that the data contained within it, has not been accessed since September 2016, the folder and it's contents can be deleted. If at any point, the Paid WiFi feature is enabled again, the data will simply be recreated.

Paid Wi-Fi Services enable you to get online by buying Wi-Fi at the hotspot through Windows Store. Windows will temporarily connect to open hotspots to see if paid Wi-Fi services are available.

How to configure Wi-Fi Sense and Paid Wi-Fi Services on Windows 10 in an enterprise

To add more to the top voted answer by @RamHound, it is completely safe to remove that folder now. The functionality has been confirmed as defunct.

On the 7th February 2019, Microsoft updated this link to state that this service is no longer available.

Paid Wi-Fi plans are no longer offered from the Microsoft Store. In Windows 10 (version 1709 or earlier), the Find paid plans for suggested open hotspots near me setting will still appear in Settings > Network & Internet > Wi-Fi . However, regardless of if you have it turned on or off, you won't be offered paid Wi-Fi plans from the Microsoft Store. Paid Wi-Fi hotspots will still appear in the list of available networks though, so you can still connect in other ways.

The 1803 update of Microsoft Windows 10 that removed the functionality did not clean up the folder. Deleting C:\ProgramData\Microsoft\DataMart will regain 527.9MB of space.