I don't believe the OP is a developer. And just because you walked out of the store like you did, that does not negate what is in the contract you signed. Apple just didn't hold you to it that day. Unless I am misreading, both of those contracts state (in so many words) that installing the beta (developer or not) means that you are on your own, if something happens to your device while using said beta. An Apple employee "may" help someone when they aren't legally obligated. That isn't the same as it not voiding the warranty, which installing the beta does, in as far as both contracts are concerned.
The following is taken from Applecare:
"This Warranty does not apply: (a) to consumable parts, such as batteries or protective coatings that are designed to diminish over time, unless failure has occurred due to a defect in materials or workmanship; (b) to cosmetic damage, including but not limited to scratches, dents and broken plastic on ports; (c) to damage caused by use with another product; (d) to damage caused by accident, abuse, misuse, liquid contact, fire, earthquake or other external cause; (e) to damage caused by operating the Apple Product outside Apples published guidelines; (f) to damage caused by service (including upgrades and expansions) performed by anyone who is not a representative of Apple or an Apple Authorized Service Provider (AASP); (g) to an Apple Product that has been modified to alter functionality or capability without the written permission of Apple; (h) to defects caused by normal wear and tear or otherwise due to the normal aging of the Apple Product, or (i) if any serial number has been removed or defaced from the Apple Product."
The following is from the Registered Developer Agreement
"13.
No Warranty.
APPLE AND ITS AFFILIATES, SUBSIDIARIES, OFFICERS, DIRECTORS, EMPLOYEES, AGENTS, PARTNERS, AND
LICENSORS (COLLECTIVELY,
APPLE
FOR PURPOSES OF THIS SECTION 13 AND 14) DO NOT PROMISE THAT THE SITE, CONTENT,
SERVICES (INCLUDING, FUNCTIONALITY OR FEATURES OF THE FOREGOING), COMPATIBILITY LABS, DTS SERVICES, OR ANY OTHER
INFORMATION OR MATERIALS THAT YOU RECEIVE AS A REGISTERED APPLE DEVELOPER (COLLECTIVELY, THE
SERVICE
FOR
PURPOSES OF THIS SECTION 13 AND 14) WILL BE ACCURATE, RELIABLE, TIMELY, SECURE, ERROR-FREE OR UNINTERRUPTED, OR THAT
ANY DEFECTS WILL BE CORRECTED. THE SERVICE IS PROVIDED ON AN AS-IS AND AS-AVAILABLE BASIS AND THE SERVICE IS
SUBJECT TO CHANGE WITHOUT NOTICE. APPLE CANNOT ENSURE THAT ANY CONTENT (INCLUDING FILES, INFORMATION OR OTHER
DATA) YOU ACCESS OR DOWNLOAD FROM THE SERVICE WILL BE FREE OF VIRUSES, CONTAMINATION OR DESTRUCTIVE FEATURES.
FURTHER, APPLE DOES NOT GUARANTEE ANY RESULTS OR IDENTIFICATION OR CORRECTION OF PROBLEMS AS PART OF THE SERVICE
AND APPLE DISCLAIMS ANY LIABILITY RELATED THERETO. APPLE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING ANY
WARRANTIES OF ACCURACY, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. APPLE DISCLAIMS
ANY AND ALL LIABILITY FOR THE ACTS, OMISSIONS AND CONDUCT OF ANY THIRD PARTIES IN CONNECTION WITH OR RELATED TO YOUR
USE OF THE SERVICE. YOU ASSUME TOTAL RESPONSIBILITY AND ALL RISKS FOR YOUR USE OF THE SERVICE, INCLUDING, BUT NOT
LIMITED TO, ANY INFORMATION OBTAINED THEREON. YOUR SOLE REMEDY AGAINST APPLE FOR DISSATISFACTION WITH THE SERVICE
IS TO STOP USING THE SERVICE. THIS LIMITATION OF RELIEF IS A PART OF THE BARGAIN BETWEEN THE PARTIES. To the extent that Apple
makes any pre-release or other products, services or information related thereto available to you as a Registered Apple Developer, you understand
that Apple is under no obligation to provide updates, enhancements, or corrections, or to notify you of any product or services changes that Apple
may make, or to publicly announce or introduce the product(s) or service at any time in the future."