When you are recording a video to the SLVR, you need to make sure that you are specifying that it will be stored to the removable SD card. This card contains 512Mbps of memory. The default setting for recording may be to phone's memory, which is only 9Mbps. Not to mention that it already contains things such as addresses and other information.
With the address book, you can specify it so that it would store to the SIM card or the phone's internal memory (on GSM phones). Also, the video storage location can be specified as well. There may be a maximum time allowed for recording so that the video does not take up all the space in the phone. Therefore, it will not allow anything else to be saved on your phone. The SD card in the SLVR is mainly for I-Tunes versus video.
There may be a setting that limits the video time as well. The wireless providers use either the SIM card number from GSM providers (Cingular and T-Mobile) or the ESN number on a device (Verizon and Sprint) to associate your wireless number. These numbers should never be given out to anyone except your provider (or authorized reseller). I can't imagine why a game company needs your IMEI number, except because they may put that into a database to associate you with the "license" he is providing to you. There is no way that he can track your IMEI since it is not sent through anything wirelessly. Personally, I would not send your actual IMEI.
I would take a look at your IMEI on your device and then change the last three or four digits and send that to him. He won't know the difference, believe me. It's the first 5-7 digits or so that identify the type of device, so if you tell him you have a Motorola Razr, for example, and he knows anything about IMEI's, he will know that the Razr's IMEI starts with 3571234, for example (not real, just an example).
I think you will feel more comfortable if you do this and I don't think that it will cause you any problems with the game. In some cases, sending the IMEI number is fine. Some people will need it to prevent software piracy. Each phone has a unique number to identify it, so once the person has your IMEI number, the pass code will only work for your phone. It's just a safeguard to prevent you from passing the game onto someone else.
An IMEI number is also used to disable a phone, so for example your phone was stolen, if you were to contact your network provider quoting your IMEI number, they'll be able to disable the phone, so whoever has it won't be able to use it, even if they were to place their own sim card into it. Of course, I'm sure network providers ask security questions first to make sure you were the owner of the phone.
Victor Epand is an expert agent for BuyCellularPhones.info, a huge cellphone superstore featuring great prices and rebates on cellphones including Motorola, Samsung, Nokia, Audiovox, LG, RIM Blackberry, Sanyo, Sony Ericsson, and others.