When did the WBC, WBA, & IBF stop stripping someone for unifying with WBO???

[Sweet Pea Pacquiao]

For years, all three of the sanctioning bodies (WBC, WBA, IBF) would strip a fighter if they tried to unify one of those belts with the WBO. Now all of a sudden, you can.

When did they start doing this? I think when Hopkins beat DLH, it was the first time someone didn't get stripped.

[BigEars]

Earliest I can think of is 1997 , Ricardo Lopez unified the WBC and WBO Minimumweight titles by stopping Alex Sanchez is 5 rounds .

[NBT]

The WBA allowed it for the first time in 2002 Acelino Freitas - Joel Casamayor