You misunderstand some of the points.
No one has suggested that OP attend an OV without disclosing to D-3 coach.
OP has revealed in a prior thread the two schools involved, but now there may be more D-1 schools than just the named Ivy League school.
OP has written in his other thread that he prefers D-1 track & field.
OP knows the other schools in question, knows his academic & athletic qualifications, and knows other athletes who have protected themselves.
OP has received advice. OP should discuss with the relevant parties his concerns & desires.
It would be helpful if OP shared more information such as if both the Ivy & the LAC made offers at the same time,which would he chose (and why).
Clearly, OP has doubts or he would not have started this thread.
OP is aware of variables that we as readers do not know.
My advice remains the same. However, this does not mean that OP should do or not do anything as the advice is just another factor for OP to consider.
After reading this thread, I feel sorry for OP and suggest that taking a long run may help sort things out.
If the LAC is truly OP’s first choice school, then congratulations. But, I suspect that OP is having second thoughts or he would not have started this thread. Also, it may not be much fun for one with recruitable D-1 times to compete in D-3.
And I think that it is safe to say that OP intends to participate in the sport at college or university.
P.S. I think that there is a bigger issue in OP’s situation that should be addressed nationally. OP has to commit to a D-3 school in order to get a verbal “promise” of support for his admission. Everything is now in the hands of the D-3 school which can outright reject OP even though OP sacrificed D-1 Ivy League opportunities. Where is the fairness to the athlete in this process ?
Recently the US Supreme Court neutered the NCAA’s draconian rule over the lives of D-1 athletes. Justice Kavanaugh wrote a scathing rebuke of the NCAA and its improper use of its power. D-1 athletes are now allowed to profit off of their NIL = name, image, and likeness, and D-1 players are now allowed to transfer schools without penalty if they so desire.
What options do D-3 recruits have if the school rejects their application for admission ? Absolutely none.
Is this fair to D-3 recruits who have sacrificed other opportunities based on the unbinding encouragement of a coach to “give his support” to the athletes application for admission ? Of course not. It is an outrageous, antiquated system totally in the control of the D-3 college which has to answer to no one regardless of its decision & “promises”.
OP: If you are really a D-1 caliber athlete with adequate qualifications for admission to an Ivy League school, then carefully think about what you are sacrificing in order to be subject to the whim of a D-3 LAC. Plus, if you truly have D-1 times, you may be very unhappy competing at the D-3 level. College / university is a time to grow, a time to test yourself, and a time to do your best.
Standard cautionary advice is “trust but verify”. D-3 athletes do not even have that chance.
Forget about the guilt trips others are trying to place on your shoulders. Fair is fair. If the D-3 school is free to reject you for any reason or no reason at all, you should be wise enough to protect yourself & to honor your other commitments with full disclosure–which is more than the D-3 will do for you.