I depends on the state and the insurance company. In some states it is required that insurance companies include glass coverage in other states.....you need to check with the insurance company. One reason I went with Progressive is that they would include $100.00 deductible for an extra $38.00 per year. I live in California.
When I got a quote from GS, they didn't offer that extra coverage and said it would be covered under my comprehensive. ($1000.00) been there done that....... Went with Progressive.