1 Bridesmaid Dress - Should I go w/ her?

My sister lives in the UK - she got her dress this week while in NY & went home
My FSIL will start looking for something off the rack this week - should I offer to go w/ her??
Should I tell her to put it on hold and I will go see it??
I know she has good taste and I trust it - I told her as long as it's close to the color, that would be fine - style length and all that is her choice...
How do I approach it w/ out insulting her...I don't mind if I don't see it b/c she loves fashion and will look good b/c she is thin.
Any ideas??

Casually ask her if she wants you to come- some people like a 2nd opinion.

If she doesn't tell her that if she isn't sure about the color or can't decide between 2, get them as long as they can be returned & you'll help her decide.

I would definitely offer to go with her. It has nothing to do with trust, but I am sure she will want your opinion and your company.

Phew
I just got off the phone w/ her...
I am going to go shopping w/ her and my FMIL next Sat.
She sounded excited so that's a little weight off my shoulders
I really thought that they may not want me to join them - I am insane!!