before jiraiya lost his arm

[2justin9]

he was in sage mode why couldnt he sense someone approaching not to mention ma and pa

 

[Edo Odin]

They made the mistake of letting his guard down. Sensing is only something a person can do when they use their chakra. They thought Pein was dead, none of them was using their chakra to watch out for further opponents, which in turn led to their downfall.
..............​

 

[Kakashi Hatakeo]

They made the mistake of letting his guard down. Sensing is only something a person can do when they use their chakra. They thought Pein was dead, none of them was using their chakra to watch out for further opponents, which in turn led to their downfall.
..............​

Well that was stupid they should only let it down when away from the area

 

[AlphaScythian]

Not every sensor can track multiple targets in heat of battle.
Jiraya really never had any great sensing as far im concerned

 

[Edo Odin]

Well that was stupid they should only let it down when away from the area

Indeed. Hence why Pein commented on that just before he ripped him apart.
..............​

 

[2justin9]

good point guys

 

[Xāvî1]

Plot no jutsu

 

[JIRAIYA perv]

They made the mistake of letting his guard down. Sensing is only something a person can do when they use their chakra. They thought Pein was dead, none of them was using their chakra to watch out for further opponents, which in turn led to their downfall.
..............​

this ^^ though i still think that one of them (Ma/Pa/Jiraiya) should have been able to sense the Path's/chances of the THREE missing them are slim/awkward.

OR

it was for the sake of the plot.

 

[Champ]

Jiraiya never mastered Sage mode, so he was no sensor

 

[scorezor]

Jiraiya never mastered Sage mode, so he was no sensor

that is wrong. "the real one isn't here".

 

[KingHashirama]

Pain would've been f*cked if Jiraiya knew the secret.