Dealership put Def in my washer fluid tank how bad is it?

I am currently waiting at the dealership while they flush the system and wash my car, but I wanted to ask if there is anything I should do or ask to make sure I am covered.

They filled it with def yesterday and I washed my windshield this morning around 8am and when I came out around 3pm I noticed what looked like dried salt all over my windshield and wipers.

After looking it up I found that def is mostly urea and shouldn't be too harmful but I wanted to ask the folks that know more than I do as I doubt the dealership would tell me anything that could be bad for them.