nope, you should not have any problems. on your outbound, UA sets your baggage allowance, and when interlined through, the bags are just transferred to the next carrier and you should not have to pay anything. On the way back, though, you'll have to look at ET's policy to figure out how much you can carry. Flights to the US should follow a piece concept, so per *A rules, you should get the standard allowance for your cabin class + 1 extra piece. Hope this helps. Good luck!