Request: Ability to configure a UI warning on buy

With Backpacks, we like to sell Backpack slots for RP in the Shop. This works great and always has. However, one problem is that when the Backpack is at the max number of slots allowed to the player, the Shop will of course take the player's points, but Backpacks (as expected) will not add any slots.

We'd like to be able to warn people of this behavior in the shop itself. The info button on each item, though, is pretty easy to miss and many of our players don't use it or even seem to notice it's there.

A nice addition would be the ability to configure a UI warning message for specific shop items that will be displayed when a player adds that item to their cart in the shop. This would allow us to display important information to the player that might influence their decision to buy and somewhat mitigate the risk of them doing something like what I described above.