Don't see any evidence of these popping up international routes yet. I'm going to say AA looks to be primary instigator here as I'm seeing them on quite a few routes out of PHL and CLT hubs. DL and UA don't really seem to be using them out of their own hubs so much other than some very tiny markets. Here's AA fares out of PHL to various Florida markets for 1 vs. 2 passengers. While MCO and TPA don't have them. Markets such as PHL to TLH, JAX, GNV, SRQ, RSW, PBI, MIA, FLL, and EYW all have them.