I'm inclined to take the common HN position of "trying to lock people out of modifying their own stuff is bad", however there are plenty of situations in which someone who is not the owner might access an NFC tag and try to make it do things the owner does not want it to. Bricking it seems like the nuclear option, but it's not inherently evil to offer the option of NFC tags that are both tamper-resistant and tamper-evident.