Unless you had issues don't assume you will. Many of us tow cars with brake assists units. If we all had dead batteries at the end of the day I'm guessing those brake assists would go out of business.
I would not want a running car behind me, that would feel like an accident waiting to happen, who knows it may even be illegal.
If you're really concern about a dead battery then purchase a battery jump box in the unlikely event you would need to use it. Most even have a plug in that you could use to run the brake assist off instead of the jeep if you're really concern.
If you have a good battery, and their is nothing that is pulling power while you're towing you should not have a problem, even after a few days without starting the Jeep.