There really is no guarantee for security out there in any program.
And I have more then a few million out there parked in a variety of programs.
Every day can or could bring a new twist.
Diners Club allows transfers from United Mileage Plus to your Diners Club credit card. This has been an ongoing partnership for a number of years now. You can then transfer from Diners Club Club Rewards back to most other airline programs at a 50% loss. However at the select times through the year they offer times where you can do a transfer and earn 75% Bonus as they did this year with British Airways. Last year it was 100% Bonus.Where we broke even.
LH is just not the program United is from most sources I've heard from.
And the Int programs many of them don't translate into good sense most of the time.There are still some I believe that have expiring milesl So check the fine print regardless of your decision.