I've been negotiating BB in my arrangements for the last 10 years - always.  The negotiation process includes establishing mutual trust, discussing testing, no-guilt notifications and often allowance adjustments.  Of course, asking for BB has meant a lower close rate for me, as some POT's just won't go for it (either they didn't trust me, or they didn't trust themselves).  

 
I will add that, perhaps as you observe, it's been an easier path in the last 4-5 years, probably due to several factors:  
- Tests are easier to get, cost less and are more trusted as meaningful
- The social stigma against BB has lowered a lot, especially with post-millennials. (Perhaps a consequence of increasing awareness and availability of Plan B in pharmacies and online.)  
- The deep-rooted fear of catching HIV we all felt in the 80's and 90's has faded with SB's who were born 20 years later.  
 

Even in the TER General Discussion Board, BB discussions seem to pop up rather frequently in the last few years. Yes, they include wildly different opinions pro and con. But pre-COVID, and certainly pre-2015, even mentioning BB in a TER review or discussion could get the poster "in trouble" with Admin and other posters.  

 
In other words, BB has now creeped back into the zeitgeist of sexual activity discussion and practices.   I express no judgement on this, besides my own PERSON decision to seek BB sex.  Each of us - SD, SB, Escort, Client, and civilian - must do as their comfort level and conscience allow,  

 
Life is good

 
The Cat

I'm pretty much only interested in BB arrangements. That's why I look for exclusivity.  I've had several arrangements where neither of us were seeing other people.  At least we agreed to it.  Can't guarantee they didn't cheat.  I know some did.

I also don't have arrangements with women in relationships.  Who knows if their partner is also fucking other people.  

The process and potential flags.
1. discuss it early.  Discuss tests.  Agree to get tested before the first date.  If she refuses, cut it off.  A girl who's not willing to get tested or discuss tests is dangerous.  She may be escorting.  She may have something permanent and refuses to tell you.  Or just too scared to know.  None of these bode well.
2. Talk about exclusivity and going raw.  If she refuses to ever go raw ask why.  Many times they are not wanting to be exclusive and want to have multiple SDs, ie, escorting.  Or they have a partner and are cheating.  Meaning not risking getting something and getting caught.  This leads to drama I don't want.
3. If she's hesitant, offer to use condoms first date.  Get to know me. See if you want to see me again.  That can be double edged.  Some girls really are just looking to hook up once to cover rent this month.  So, I get to see if she's worth pursuing and she gets to see if I'm worth trying BB with.
4. If it's still a no, I usually move on.  Say we are looking for different things.  I'm looking for an exclusive arrangement where we get to know each other.  Doesn't have to be a relationship, but I'm not just looking to pay for sex.  Again. If she's not an escort that will trigger that I value her as a person.  Which I do.  And I'm willing to help her through the anxiety she may be going through.  Or I know to move on.