Before 4G, there was 3G, and with 3G, public IPs- sounds like an excerpt from the Book of Genesis. With the revelation of 4G, wireless carriers attacked the subject of the world running out of IP addresses head-on, and began spoofing wireless devices' public IP addresses, AKA, a derivative of NAT. Subsequently, should one find themselves remotely accessing their video system via 3G one day, the moment they chose to upgrade to 4G, WOOPS, a rude awakening no one was prepared for, and certainly one wireless carriers made no mention of.
During my tenure at NUVICO, this is something I have experienced several times over. Your customer has a 3G air card mated to a Cradlepoint router, all is well, "Hey, I can go with 4G", and suddenly, no remote connectivity. In the first phase of 4G air cards, carriers were claiming, only after having been passed around like the proverbial dooby from first, to second, to third, to 'God knows what tier' of technical support that actually had SOME working knowledge on the matter, that they were aware of the "problem users who need remotely connectivity are experiencing, but there is currently no action in place to resolve these matters." Oh, and 'by the way', no, you can't "revert your service back to 3G," so you're just out of luck.
Fast-forward to mid 2012...
Verizon and AT&T announce static IPs available for 4G users... Cough cough, with a small activation fee of $500, and a monthly recurring charge of $25 in order to maintain that static public IP. Sad, awful reality, but I'll tell you what, if it isn't one hell of a fast connection once she's all up and running!
So yes, there's always that... or a DDNS that relays video to a data pool for truly seamless port forwarding REGARDLESS of a carrier's disdain for public static IPs- there's also that.