If you have it set up properly, why would it be unsafe?
This was my bumperpull setup. Worked great once I got the sway bar installed on the camper. Before the sway bar it was crazy.
The gooseneck makes it rock solid. No feedback at all.
I do it all the time. Comment above about bumper/bumper is valid. Lots of feedback but I got a sway bar for the 2nd trailer and it is now rock solid.
Towing behind a gooseneck is great though.