Ok I just found this

Passengers traveling on United Airlines (UA) carriers are subject to United's contract of carriage, which is available for download at united.com. The contract of carriage governs matters such as:
• Check-in requirements for domestic and international travel, including information about when service may be refused;
• Limits on liability for delay, damage or loss of baggage, including fragile or perishable goods;
• Claims Restrictions, including time periods within which a passenger must file a claim or bring an action against the UA Carrier;
• The UA Carriers' rights and limits on liability for delay or failure to perform service, including schedule changes, rerouting and substitution of alternate air carrier, aircraft or mode of travel;
• Rules on overbooking and reconfirmation of reservations; and
• Baggage policies, including carry-on allowances and size and weight restrictions for checked bags.

So Thai is a UA partner are they considered a UA Carrier since the ticket came thru UA if so it would seem the UA check in rules would apply no ? Don't mean to be a pain in the ... thanks for all who help