Getting too many backlinks in a short period - Aggressive backlink penalty ?

Excessive backlink penalty ... reality or not ?

In our office a hot group discussion conducted based on the topic excessive back link generation in a short period of time. Group is divided in to two based on the criteria whether they follow fast aggressive back link generation to promote their website or only following slow and steady back link generation. As we expected our colleagues took this topic very seriously and various points came out during the discussion. Majority accepted the fact that they are generating too many back links for their websites to improve the PR and SERP of their websites even though they know it can lead possible google penalty. But some guys opposed this google penalty idea for excessive back link generation. According to them google cannot penalize any website for incoming links but out going links can lead to google penalty. So here I am writing down the major points we collected in the topic "getting too many backlinks in a short period may lead google penalty".