Have you experiences any issue with this?

The primary suite in my home includes a toilet compartment that shares a wall with the bedroom. We installed sound batts. No issue. No need to constrain designs nor make the toilets less accessible.

@Mark Bischak, Architect yes! I live in a very nice, spec built house and this is one of the things I absolutely hate about my bathroom. I'm lying in bed reading or whatever and I can hear everything that's going on in the water closet which is about 6 feet from me. The exhaust fan covers none of the sound. The bathroom has a water closet, tub and enclosed shower (with actual walls, not just glass) all on the exterior wall. I'll never understand why the shower and the WC weren't swapped. I've seen poor toilet placement in a lot of floor plans (e.g. powder room toilets sharing a wall with a dining room, or kitchen.)

The other thing I don't like about my floorplan is if the door is open to my room there is a direct line of sight from the living room to my side of the bed but that's a different post ;)

@Charles Ross Homes I'm glad to hear you did this in your own home...I guess my plea is, please do this for the homes you build or design for clients. And if you do, thank you! That same wall in my bedroom extends to the ceiling, which is 16' and the upper part is shared with my son's room. If my husband is watching a loud movie in our room, I can hear it in my son's room. So now I need to figure out if I could retrofit insulation of some kind to help with all this noise transfer.

Yes, it's our standard practice to install sound batts (mineral wood insulation) in walls between living areas and baths or bedrooms, around the Powder room, and between Bedrooms and bathrooms.

Before spending money on insulation, spend some time figuring out the travel path for the sound between rooms. If both bedrooms share common HVAC return ductwork, the addition of insulation might not help much.