The icemaker has a heat strip in the water line FROM the solenoid to the icemaker and it is also wrapped around the solenoid. So, if you are using the trailer, there will be power to run the heat strip. A problem can arise in the line feeding the solenoid--it usually is not protected by a heat strip. Also, if your fridge is located in a slide, there may be a section of water feed line that is exposed to outside temps--that seems to be left to the owner to figure out how to protect it.
As for myself--if I happen to be out in temps that may cause a line freezeup, I just turn the icemaker of, drain the feed line and make ice the old-fashioned way--with trays.
This is in reference to DRV models only, not too familiar how other mfgs try to handle this.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired