The reason to do this is to take the early a.m flight from MIA to MGA on a Saturday by leaving late Friday and staying at the MIA hotel. Arrive at noon Saturday vs. 6 p.m. Saturday.

So this seems to have been the same A/C each day but there is a risk that it is delayed ex-YYZ, and they use a different 738 to MIA and then I get in later or not at all in MIA. Since I am staying overnight getting in late doesn't matter. Even not at all might not if there are early LGA-MIA flights on Saturdays.

JGR01 assumptions as to bumps or upgrades are not the reason - I fly paid J or full fare y with miles upgrades.