Personally, I would not, for 2 reasons..
When plugged into the tow, you are supplying DC to the trailer and battery. The trailer, once connected to AC source, then charges the battery and runs the 12volt. I would not want the converter in the trailer to send the dc back to my tow battery.. Just bad juju to me.
IF there ever was a surge in the 50A supply, it is possible to sent it all the way into the tow vehicle, disabling both.