Sony Ericsson Xperia X10 :: De-brand Warranty Void?

I briefly spoke to SE UK on the facebook page and asked about de-branding the phone, I was told that was would void my warranty but the only explanation given was that 'thisis classed as tampering. It is also not something we would recommend as this could damage your handset'

I followed up with a couple more questions but have recieved no reply so thought I would bring it over here instead.

First up, de-branding the phone does not involve rooting it so the process of rooting can't be the reason for the void.

I want to know why updating the phone with an official, SE approved update voids the warranty?

I also want to know why Sony themselves don't provide an option of just updating the phone with the generic update instead of making us wait for the networks to release it?

Or is this all simply about money, are Vodafone etc paying SE a healthy amount to not let us de-brand and remove the useless unused app's that they put on?