AC,
First of all I never used the word IGNORED or All as part of my response. Surely not ALL lenders operate the same but with fewer and fewer to chose from the table will be set by a select few.
Second, I learned more than 10 years ago that GUIDELINES are not RULES. A guideline is any document that aims to streamline particular processes according to a set routine. By definition, following a guideline is never mandatory (protocol would be a better term for a mandatory procedure). Guidelines are an essential part of the larger process of governance.
So to answer your question would be impossible because I don't use ALL lenders but I can give you an example of a GUIDELINE that was IGNORED by Wells Fargo (I think they are now either the largest or second largest in the nation and may qualify as one fo the 2 or three big boys you described earlier in this thread).
Fannie Mae allows a borrower who has successfully completed a Ch 13 bankruptcy to obtain a Fannie Mae loan two years after discharge (Refer to https://www.efanniemae.com/sf/guides/ssg/annltrs/pdf/2008/0816.pdf). Wells Fargo requires borrowers regardless of bankruptcy type to wait 4 years.