I have 2 important cautions about "canned air" type products:
1) Never spray into / onto a fan unless you have a way to keep the impeller blade(s) from spinning. The force from the spray against the blades can easily spin them and exceed the fan's design maximum RPM and damage things. If you can't reach it with your finger, using the "straw" left over from an empty canned air can will usually do the trick.
2) Never spray onto electronics which have not completely cooled down to room temperature - the thermal shock of the cold gas hitting warm / hot components can cause fatal damage.
This is correct - and actually, I don't advocate using canned air inside the print chamber, at all - I suggest vacuuming.
If one is plugging and unplugging ribbon cable examining the connectors, it presupposes that the machine is:
A. Off
B. Has been off and is cold since it is not working (which is why the connections are being checked).
C. We're not talking about fans in this instance.
So yeah, don't use canned air inside the machines unless very careful about it and in specific circumstances.
By the way, welcome to Luminous Landscape Forum.
Mark