[AlSar]

Nukey Shay

It CAN leave is not correct. Because it WILL leave this marker and it seems to be left there forever.
Some tricks of such kind leave a mark near Staunton construction site, in the place where no marks are intended during all the storyline.

As for myself, I'll use old 'high vehicle method' too. Because I'm not satisfied with weird additional markers.

[Nukey Shay]

I posted "can" instead of "will" simply because I didn't fully research the problem with the minimap (have you?). AFAIK, the blip may be removed sometime later...unless you know for a fact that this is not the case under any and all circumstances ;-)

It also should be suggested to anyone who chooses to use the method might want to save the game before attempting. If you miss the timing when releasing the sub-mission trigger inside the garage, the cutscene will get stuck and you'll be forced to restart from your last save point.

[AlSar]

Nukey Shay

Our Russian community already had some experience with this method.
The marker is likely to remain even after 100% completion.

And saves - it's better to save after every mission if you acquire special vehicles.