Total misrepresentation of what happened by OP and what the ride will have been asked to sign.
This isn’t a waiver. It’s acknowledgement that Bride is choosing a dress which is too small currently and she is signing to acknowledge that and the fact she will pay for it if it still doesn’t fit.
£450 for alternations is what the shop is charging for the bigger size to be adjusted to fit.
Of course she could walk away and buy neither the dress that is too small currently, or a dress that needs adjustment.
There has been no ‘forced’ about it. Bride was given 3 choices - bigger dress with £450 alterations, smaller dress which currently doesn’t fit (clearly not recommended by shop - hence requirement to sign to acknowledge it doesn’t fit and accepting responsibility to pay) or option to walk away.
Bride CHOSE the go with smaller dress option.
In my view it was a daft choice. She might not fit in it. She will then need to rightly pay for the dress and face stress of looking for last mi Ute alterations, which might not work and the shop is unlikely to be willing to attempt, knowing the dress cannot be made bigger.
Wedding dress shops have seen it all before. The overly optimistic bride who thinks she will slim down to fit the dress…..and then doesn’t. The shop are left with someone blaming them that it doesn’t fit or demanding impossible alterations or refusing to pay for it. By far the safest option is to have a bigger dress that is adjusted to fit you close to the event. Of course you pay for this extra work, but you factor it into the price you’ll pay.
If you can’t afford the dress AND the alterations you choose a different dress that either fits perfectly OR a cheaper dress that is affordable with the necessary alterations.
If OP is still reading this, I’d advise her to get onto friend and tell her to ring the bridal shop ASAP and see if it’s too late to change to the bigger dress - this would be far better.