I have a fellow friend doing this WOE. She just started and she was never a big water drinker. Since you need to drink water -lots of it to be healthy - she has struggled with it. She finally decided her compromise would be Crystal Lite. Her theory is that since it has no caffeine etc, it will count as a water unit.

This can't be right, can it? I told her I didn't think it was but she brushed me off. I just hope she doesn't get too dehydrated from not drinking regular water.

She won't become dehydrated, but she's not getting the full benefit of drinking plain water, either, and no, Crystal Light does not count for water. Only pure water counts as water. Crystal light is sweetened with Aspartame which is a known staller for many low carbers and generally discouraged by Dr. Atkins in general.
Something she can try is to gradually mix plain water with her Crystal light, watering it down until she is drinking mostly water or try lemon or lime slices in the water. It also helps to experiment with the temperature of the water itself; some people like their water room temperature while other like it ice cold.
Another possibility is to drink bottled or filtered water instead of tap water. I have a friend who won't drink water unless it's filtered or bottled.
Of course, drinking Crystal Light instead of water is her choice, but honestly it's really no better than drinking decaf diet pop except that at least it's not carbonated.

The bottled Crystal Light is sweetened with Splenda, so if she's drinking that it's not as bad for her.

I was the same way until I just started keeping the fridge at work stocked with bottled water. Since it was always there I would just drink the water instead of buying a soda from the vending machine.

Now I drink a huge bottle of water (64 oz) just about every day at work. Other that the frequent trips to the bathroom I think I feel much better than drinking diet soda like I was before.

I still have an occasional diet soda in the evening, but I try to make it a treat instead of a staple.

She might want to try unsweetened kool aid and sweeten it with splenda as an alternative to the powdered Crystal light. Plus kool aid is much cheaper.