It depends on many factors with the main ones being your stats, previous adherence and cruise/blast doses. As posted if you have just competed and are super lean then you could "gain" very well on a cruise dose. Although in that period I would recommend a basic/low dosed cycle containing non toxic compounds (test, deca, primo etc). Then after taking advantage of that rebound you could go on TRT and maintain the best you can.
Other times people can progress on a cruise because like qbkilla stated they basically fucked up beforehand and weren't eating and training optimally. Someone's level can also come into play. Another similar subject highlighting this are the amount of guys who look better now on lower doses than what they used 5-10 years ago because they improved all areas so even with lower drugs made more progress.
There is also the definition of "progress". I go on a cruise and I drop water and look better so if I can maintain that look you could say I progressed. Am I going to put on 10 pounds of muscle on a cruise... no chance.
I think with subjects like this common sense just needs to be used. Someone freaky on higher doses is going to struggle to even maintain nevermind progress on a cruise. Middleground guys could maintain well and maybe even improve their look but they won't be putting on pounds of muscle. Lower standard physiques could improve especially if they weren't training/dieting optimally beforehand but if they were then small progress or maintenance is the best they can do.
Generally for most people on a cruise we are just trying to maintain the best we can. Everyone has different preferences and on a cruise I will drop water so if I stay on a great diet I look better for 90% of the population but for bodybuilding I will eventually lose fullness, lose pop and lose freakiness (hard and vascular). No amount of dieting or hard training can duplicate the look 1.5g's of test, mast and avar gives.