The two runways are fairly close together at KSFO - much closer than at Heathrow. Still it must be a little unnerving for passengers. You can actually try this in FS. I have landed at KSFO rwy 28R with an AI landing at 28L. Never been exactly parallel with the AI though.
That is actually kinda unusual to see close parallel like that. Usually they try to stagger them by about a half mile to make it easier on the pilots because the PNF has to keep the other aircraft in view during landing.
Minneapolis also has close parallel approaches like that and during bad weather has a dedicated controller who watches the approaches with a special high-update radar that gives position updates less than every second for aircraft on the approach.
I've experienced it a few times at SFO. And LAX was another airport where it used to happen occasionally.
Funnily enough it happened in FS a couple of days ago at JFK when an AI 747 glided alongside me on approach. I thought it was pretty cool until I realised he was landing on the same runway as me
Ian - Have you tried AISmooth or something similar? Mind you, while it does reduce the chance of that happening, I have had a simultaneous same runway landing with AI on occasion.