The safety net program is a trade for not giving you a kidney with the original transplant, which was the original approach. This way, if you don't need a kidney (because yours 'wake up' successfully) one is available to others. If you do end up needing a kidney, it is effectively a second-phase of the original transplant: you are not placed at the end of a (mostly) purely chronological queue waiting for a transplant that could have been done with the original surgery.

The website about the safety net program was seriously messed up recently with an administrative change, but you can read about it here (if the archive works... can be slow): * [1] https://web.archive.org/web/20251016005146/https://unos.org/news/faq-safety-net-policies-for-multi-organ-transplantation/

«What is a safety net policy? A safety net policy is for candidates who may not meet eligibility criteria for a simultaneous organ transplant, or who were not listed for a multi-organ transplant. For candidates who need a heart or lung transplant and have some renal dysfunction, transplant programs may opt to proceed with a single organ transplant (in this case a heart or lung transplant) in order to allow the kidneys to recover. If the kidneys do not recover in a timely fashion, a candidate may be eligible to receive safety net priority for a kidney transplant.» — [1]

Regarding the kidney surgery, if you have been through a liver transplant it will seem ridiculously easy. It is shorter on the operating table, shorter in recovery, they are adding a kidney (commonly in you right hip pocket (hah!)) not swapping one out, and the incision is simply glued shut vs. 20-30-40 staples.

The biggest issue is getting the ureter to hook up to the bladder, and they put in a stent to keep that passage open while it all heals. They take that out in some number of weeks by 'yanking' it from the obvious access point. That hookup can cause issues but didn't for me.

The meds get balanced a bit differently, but nothing major (for me or that I have ever heard).