I suspect he has cluey law enforcement where he lives- and if he opens the bonnet and has no MAF sitting in there, he may get a defect/offense.
I've heard of people plugging the MAF back in to make it appear its working, to make things look factory under the bonnet, etc. Police in my area would not even know what a MAF is or does, but I've heard some other states and areas are more aware of it.
long complicated story, but basicly brought the car he kept otr and wanted teh ecu back but havnt had time to replace with standard ecu, and had to hook standard airbox etc up so i had a filter etc
The maf itself won't. but given mafless tunes are so sensitive, the maf restricting the intake may bugger the tune, unless the maf was there when it was tuned.