[PNW Fireguy]

There are several older threads on this topic on the forum. In short there are specific racks designed for use on the rear of a towed or towable. The vast majority of bike racks are not designed specifically to be used on the rear of towables. Etrailer does a good job of pointing out the approved environment for the bike racks they sell. The web pages for the each rack clearly indicate suitable installation environments. I have a Swagman that is specifically rated for use on the rear of a towable and suitable for e-kikes.