[botts]

I guess you can still SE them using the serial number method if you know how.

Precisely- there is always a way around it.
Regarding them noticing the receipt was fake- it would be interesting to see if a better method would be claiming you have no proof-of-purchase, and claiming you have asked the company you bought it from for some proof. Then if the company thinks the POP you have provided is suspicious, you can claim that it was generated unconventionally by the company at a later date.