I have the progressive industries hardwired EMS unit, it was around $200 and it is cheap insurance and piece of mind, as the others have mentioned.
I made a “bonded plug” to plug into the generator so it doesn’t show an open ground to the EMS system. I had the same concern regarding EMS and the generator but the bonded plug was easy to make or you can buy one. Just search YouTube or google for bonded generator plug.
Here is a video about making your own
https://youtu.be/iELx2ZxVv1E
And here is a link to buy one
https://www.microair.net/products/ge...r-bonding-plug
Congratulations on your new trailer!