Na.. that will be too much work for the user, plus disabling DNT will mean it's disabled for everyone, not just the said website. It also does not make alot of sense, disabling DNT does not make site any money directly. So it will only raise suspicion in a casual user's minds, that why would the site need to track him/her when there is no apparent monetary profit to the site.

Instead they can show a banner that DNT is enabled and when it is disabled, the banner is gone.