Hi,
Can/do IMSI systems spoof tower id: is there anything in GSM to make towers self-verifying? I'm guessing no, in which the above would be very poor. No, the problem is, that mobile phone authenticates to mobile network, but the opposite is not true. Since mobile network does not authenticate itself to mobile phone, IMSI Catcher attacks are possible.
There has been also demonstration of "home-made" IMSI Catcher based on Osmocom platform last year at the CCC conference. The video of the presentation "Further hacks on the Calypso platform" by Sylvain Munaut is here: http://media.ccc.de/browse/congress/2012/29c3-5226-en-further_hacks_calypso_... So, it is very easy to set up fake cell with any cell ID.
Also of note is API for signal strength, so a mapping of known towers to expected strength at location XYZ could be used to detect systems used to home in on phones, which usually max out on signal and tell your
This would not work, because cells are not static (new cell emerge, covered area changes, etc.) and opencellid database is not regularly updated. There could also be femtocells used, etc... Regards, M.