I wonder if the idea I am going to present has ever been discussed with any sense of going forward:

Trezor does not have a serial number.  It does present a device # when connected to a site such as trezor.io or any other site/node and of course the mpk's are needed to display the balances and addresses.  That device # doesn't compromise security, BUT it could easily compromise privacy.  I operate several "hidden" wallets from each Trezor as I am certain that many of us here do.  Example; you connect a decoy/small wallet to a web wallet and use it or verify a balance or whatever.  The device # is presented, and the wallet software uses the mpk's presented.  I know all websites will say they don't log such things but I say why take any chances at all if it could be prevented by a simple software coding.  On the Trezor T there is space on the SD card if a user employs that option.

As a privacy improvement option; what if the code were changed so that the Trezor T presented a "spoofed" device # every time you connected it?  Example. When I use my daily wallet and things related directly to my name I could care less about recording the device # during a transaction.  But later if I want to view a more substantial wallet where storage is my concern, in that case I would strongly prefer that the device # provided be anonymous (un-related to previous transactions).  With this modification of code there would be NO way to ever connect the SAME device # to different mpk's thereby betraying your privacy.  Make sense?

There would be plenty of space on the SD card so memory/chip size wouldn't be a factor.  Again, this would be an option in trezorctl and not something forced upon every user.  I would most certainly use this feature without question.

BTW - I am not saying trezor.io is neglecting to forget our devices when we click on that option.  As a security buff I am saying that at some point in the future 3 letter agencies could employ enough pressure that they may have to retain information.  Electrum  nodes etc... are all under the same possibility of influence.  Surely this would be super simple code to write, and given the extra space on an SD card there is more than ample room to install it.

Any GitHub coders that would be willing to carry this idea over, feel free.  I love Trezors