Lior
As to your first question why not? Am I missing something? Assuming his posek is working within the framework of Orthodox Judaism, yet holds of the Eruv. Why cant that person carry?
Can I tell a Sefardi where to buy Kitniyos he plans to eat on Pesach?
As to your second question:
Have you ever tried asking a DD franchise if you can use their microwave? I tried this morning and was flat out refused.
Have you tried reporting to DD headqaurters?
BTW your concern regarding DD isnt limited to DD. MAybe the lays potatochip guy fried his bacon along with the potato chips yesterday. There is no mashgiach temidi at Lays and they are open on Shabbos.