Hi @asculpeous See section 2.7 of the target statement: If you accept the Offer and the Bidder subsequently increases the consideration offered in respect of that Offer, you are entitled to receive the improved consideration.
I've had a fun few hours reading chapter six of the corporations act. One thing i learnt today is that as RMS' bid is an off market one, they are excluded from buying any BRB shares on market (in most circumstances) as this would affect the consideration that must be offered under the bid. See section 6.36 of the (hopefully) attached Regulatory Guide. It would appear GS are free to vacuum up whatever is on offer.
Section 6.50 of the same document also explains the "Creep" that was mentioned earlier. All the best, Perdy