Thank you - I just did register.
a) Not sure if my flights (booked as UA-code-shares on USAir) will qualify (at check-in I will try to get the flights 'registered' under the USAir flight-number ...), and
b) not sure if the 100% bonus will be 'given' on all connecting-segments (LGA-CLT-MCO return in nov/dec, in eco, which is a total of 4 segments) and
c) not sure if the miles&more-minimum basic credit for USAir flights in eco will be 1'000 (as on UA flights in eco) or 'only' 500 miles.
The max credit I expect for me would be:
* 4 segments in eco = 4*1'000 miles = 4'000 miles (counting as status miles too)
* + 25% m&m status bonus = 1'000 miles (counting as status miles too)
* 4*dbl bonus = another 4'000 miles (not counting as status miles)
= total of 9'000 miles (5'000 miles&more status miles).
We/I will see ...