"Hey, rather than cut notches for the second pipe let's just run below the joists!!"
I never could understand why the carpenters insist on putting those wood things in everybody's way, they're just a pain.
When I was building/remodeling full time I came to the conclusion that to get a plumbers license you should be required to surrender your sawzalls.
I now rest my case.
Might not be as bad as you think - if the load needs a 2X10 out in the middle of the span, a 2X5 at the end might be within spec. That is assuming the plumber actually thought about it.
I particularly think the use of caps and couplings is outstanding.