I, personally, think this is a totally valid tactic, and wouldn’t be upset if a player used it in my game. One of the first things we go over in Session Zero, though, is that your characters, while unusual, are not unique. Any BBEG worth his stuff is capable of scrying on your tactics and hiring a hit squad that can copy or counter your tactics.
If a player started doing this repeatedly and trivialized many encounters, maybe the next group has his own sorcerer that can do that, or knows disintegrate, or can teleport the big stompy guy into the obvious spellcaster’s face. Cheese isn’t an arms race the players can win.