I've name changed as it's vey outing.
I'm in African on holiday with DH and DC who are both 10 yrs old we have been here a few times.
Staying with SIL who is lovely and has two older kids also lovely.
Problem is other two SIL's who are based in UK and are staying also (massive house and we have the guest suite 2 bedrooms two bathrooms)
Anyway decided to go see PIL's a 30 min drive oldest SIL announced she would join us although she has been here for 2 weeks and seen them several times.
I explained there was no room in cab but she insisted me her and DC could sit in back as DD is quite small she could sit on either her or my lap without a seatbelt I refused she then tried to convince DH who suggested two taxis, she ended up getting a lift and arrived 20 mins after us and proceeded to dominate conversation speaking to PIL's DH and family friend in local language which neither me or kids understand.
When it was time to leave she announced loudly that she would share our taxi as her friend had left PIL though this was a good idea I said wasn't happy due to no seatbelt for DD.
DH arranged two taxis she didn't want to travel alone so to avoid making a scene I went with her and DS in first taxi and DH and DD went in second.
When we got home I could tell she had already discussed with her sisters what happened as they were not surprised that DD and DH were not with us and also other UK based SIL and her were obviously talking about me.
AIBU to insist on DC wearing seatbelts and to find her overbearing.