Originally Posted by jsloan

Yes, there's a chance that you wouldn't be able to get your checked bag in SFO. How large of a chance, it's hard to say, but it's definitely nonzero. If you buy the ticket as discussed, neither LH nor UA is obligated to bring you to SFO. Suppose the TLV-SFO flight is canceled or delayed; UA can re-route you on TLV-EWR-SEA, TLV-FRA-SEA… even TLV-EWR-SFO-SEA, in which case your bag is going on to SEA without you, as you'll re-check it at EWR and won't see it at SFO.