There is a legal phrase called promissory estoppel, which essentially means that if your promise has serious repercussions for the other party and by not keeping it you caused some sort of harm (financial, in this casespoiler alert), youre liable for that harm and can be prosecuted
Rapid Strike Urshifu VMAX 088/163 Oversize Card
While sub-sets tend to introduce new mechanics or gimmicks to the game, full sets provide a ton of new cards to collect and form the foundation for a new metagame that could last for months
The players sat down and got set up to begin
New Game Mechanic: Keyword Counters Sometimes creatures gain abilities until end of turn, but on Ikoria, these modifications are often permanent
Not only are you getting to pick from a lot of options, youre getting unique insight into how your opponents deck works