...do advertisers think it smart to use the word "grab"? A mobile phone company invites us to "grab" a deal while stocks last. A cable TV supplier asks us to "grab" its latest contract for phones, TV and internet. There are plenty of other examples.
To grab means to seize possession of something, regardless of the wishes of anyone else. Children may grab the last biscuit. Raiders may both smash and grab as they batter down the windows of jewellery stores. But if you enter into a contract, which of course is essential when doing mobile phone or TV/Internet deals, then nothing is grabbed. Instead you, as consumer, make a offer to purchase the services or goods supplied and the supplier accepts or declines your offer. Nothing takes place without their consent so nothing is grabbed at all.
In olden times we might have been urged to "take advantage" of a special deal, or perhaps urged to "buy one while stocks last". Now the deadly hand of the admen is destroying yet another perfectly sensible word and changing its meaning. We have lost "ultimate" and "exclusive", "special" now means ordinary and "grab" is changing to mean nothing more than either "take" or "purchase". But it shouldn't. Consider the phrase "I'll just a grab a coffee" which I believe is coming into common parlance. No you won't, my friend. If you go into a coffee house, you need to order one, pay and wait while the barperson presses the shiny levers and makes whooshing noises before collecting your plastic cup which will probably give you third degree burns. Grab a hot coffee and you'll have the law after you (and you'll get second degree burns plus unpleasant brown stains down your trousers). If the word is used correctly, it works. And if only admen stopped misusing it, maybe it would revert to its real, useful, meaning in day-to-day speech.