It's hard but look on the bright side... with any luck you'll only be gone 3 days/nights. It will seem like a lifetime but looking back a few years from now it won't be that big of a deal. Heck, when we were kids, it was pretty common for hospitals to say no visitors under age 18 all the time - this is a temporary thing. So most of us probably weren't visiting our baby sisters/brothers in the hospital and it's not a big deal. Use the webcam and lots of pictures and videos... your son will be fine (as long as you are and project the right attitude!!). (tell your son it's a really cool special few days with grandma and grandpa and talk up how great that is to be alone with them!)
A friend of mine just went into labor and delivered at 32 weeks. The baby is fine, mom is back home, baby is expected to stay at hospital for at least another 5 weeks.... and she has a 3 year old and 5 year old at home who have yet to see their baby sister even though she's now 2 weeks old and mom/dad visit daily. It's very tough on everyone... be thankful if your visit is just 3 days/nights. :-)
The hospitals around here (central Indiana) aren't taking any chances and take no exceptions to the rules. It's for a good reason. I have friends who work in some of the hospitals. Since the bans went into effect, one hospital saw a 60% reduction in doctors/nurses/other staff getting the flu within a week. So many were calling in sick that it was compromising patient care. Also, the number of patients getting the flu (and all other secondary infections) dropped dramatically within a few days.