I have let several beers sit on yeast cakes for 4-5 months and the beer tasted great. I have also just thrown the wort on top of the yeast cake many times, even once 4 times in a row without noticing any off flavors. I was too scared to try a 5th. I am not sure what the big worry is about however, my pallet may not be as refined to pick out the off flavors, but so far a lot of the things I have seen on forums to be worried about never turn out to be a problem. I BIAB and use the no chill method for the most part (my issue starting this thread was because I thought I could try a method of chilling my wort down that did not work well and caused me to be up too late!).
In 3 years of experimenting with brewing the only "bad" tasting one I have had was due to over hopping with a mix of hops that did not go well together, and early on brewing at high temperatures and causing the beer to taste a bit like the wort. However maybe in time I will start to notice the subtle differences like letting it sit on the yeast cake for months and what that does to the beer. I live in constant fear of the day I will get an infection in a brew but still not had any worries, knock on wood.
This is what I was after, why waste the Co2 from the fermentation? 2 processes at once, and reduced time overall. You just would not do a true yeasty ale like this. There is also fermenting and then attaching a spunding valve when it is a certain percentage away from completing, allowing the last bit of CO2 made to carbonate the beer. I have not tried this however, this was my first attempt at pressurized fermentation and spunding.
I will see how it tastes over the weekend and report back.