Kalen, I am a "rules maven". Accredited by the R&A, USGA and RCGA. Worked tournaments in Canada, USA and Asia, including PGA Tour events.
To get technical, Decision 33-2a/12 states:
Q: It is proposed to install boundary stakes between two holes as a safety measure. It would prevent players playing a dogleg hole from driving onto the fairway of another hole in order to cut the “dog-leg”. Is it permissible to establish such a boundary?
A: Yes. For the recommended status of such boundary stakes, see Decision 24/5.
So, in the present case, the Committee could have the new tee on #17 play as in bounds or out of bounds for play on #16. It must be in bounds for #17 for obvious reasons - the teeing ground must be part of the golf course.
How it plays for the Open next year is up to the Committee for the tournament.
Decision 33-2a/13 also has some application.
Q: A Committee has decreed that ground surrounding a certain teeing ground is in bounds for tee shots and out of bounds thereafter. Is this permissible?
A: No. In play of a particular hole, an area cannot be both in bounds and out of bounds.
Finally, Decision 33-2a/14
A Committee may make a Local Rule under Rule 33-2a declaring part of an adjoining hole to be out of bounds when playing a particular hole, but it is not permissible for a Committee to make a Local Rule placing an area of the course out of bounds to a stroke played from the teeing ground only.
This is all probably more than anyone wants to know but here it is.