Part-work magazines: is there any guarantee you will get to the end?

Currently there's a rash of part-work magazines being advertised on TV. One promises that you'll have your own working model railway layout after 120 copies. (at £8.99 a copy, that's just over £1,000 for your train-set, when Hornby will sell you a starter set for £150). If I were to start buying this magazine, is there any guarantee it will still be publishing after the first flush of advertising dies off? Will it die after twenty issues, leaving me three pieces of track, a couple of carriages, half a railway station kit and no locomotive? Is this the usual way with part-work magazines?

By the way, none of the "sponsored advertisements" that may appear beneath this question are endorsed by me, I don't want to see them here, they're an intrusive waste of space and the product is bound to be total crap. Thank you!