I am a member of a Yahoo group for Lazer tag enthusiasts and members on there have (and say it is extremely easy to do) coded arduinos with just ir receivers and emitters to record an ir signature and repeat it on demand. Storing it long term shouldn't be much of a stretch. I think they were more worried about patent infringement and also wanted devices that replicated their player IDs so hits generated were credited to them. We use Hazbro "Lazer tag" guns such as the deluxe, LTAR, pheonix LTX, Drone, and Master Blaster. A search for any one of those would give a general idea of the equipment. Range is ~300 ft.

But I don't think the process is easy or straightforward since I'm such a coding newb.