As I imagine it, egos are represented by a particular kind of "file format", largely an enormous list of neural connections and their strengths, chemical and electrical parameters. This is surrounded by metadata giving egoID, names, citizenship, medical history, genetic code, neurological information, enhancement interfaces (if any) etc. This is what can be turned into an active infomorph by sending it to ego running software, sleeved by sending it to a egobridge, forked by copying and edited using psychosurgery. Then there are files containing core virtual possessions: various certificates, encryption keys, personal files, and of course the muse. This may also include information stored in various implants and external objects. When travelling all this data are wrapped in an egocasting wrapper, essentially an encrypted zip archive of the files. The key is sent by quantum link, and used to decrypt the ego at the destination. If I wanted to smuggle something I could do it by just putting it among my virtual possessions, but when being decrypted at the destination someone in authority could of course investigate them. I could encrypt it, but then I might have to explain away what that big file is. I could use steganography or onion encryption to hide it in my virtual seraglio files, making it hard to detect. I could probably use steganography to hide it among the least significant bits of my synaptic weights. That would be very hard to detect unless you knew what you were looking for. Or you could insert some extra neurons and neural network to contain the information - but that is relatively size limited.

It is a very cool idea, but I suspect it would be a little more complicated than that, if whoever received your ego didn't prune out the random garbage data that was inserted in those memories. I imagine the result would be like opening up a program and inserting random characters to some part of the memory space. The program probably won't run, and if it did, it might only work until something triggers that altered code, when it would crash. A skilled psychosurgeon could probably remove that data and insert some blank connections which would result in something like what you're describing, but otherwise it could be the case that if the ego is reminded of that trip to the water park, those associated neurons start firing randomly around to the rest of his brain, causing some sort of epileptic seizure, and possibly resulting in permanent brain damage. In all likelihood, though, some sort of checks would detect the "corruption" of the backup and it would be flagged as damaged and either pruned for you (in which case, you just lost your data) or discarded rather than resleeved. Assuming you have an ally on both ends to hide the data, and recover it for you, I think the idea would work - but otherwise that would be a very dangerous place to hide your data. Not only would you be likely to lose it, but if you didn't, the resulting ego would probably be unusable - although this is all speculation. :-)

Yeah, I suppose it depends on the relative size of the data you're attempting to hide within the neural network - and I'd be willing to believe that a map of a human brain is going to be a lot bigger and more complex than some typical black market software. Someone certainly couldn't smuggle, say, another ego in this manner without some serious damage. I still maintain that something could go wrong (if the weight of some critical mass of connections moves from one side of the activation threshold to the other), but if the data isn't large, it probably wouldn't be noticeable.