I have said plenty of time that I don't think RRSO is too cheap - just a little cheap.
As for why people are buying RRSO instead of RRS - I can only surmise that peoples expectations have increased that this stock 'could' reach some of the heady levels like 10-20c that have been bandied about.
IF you believe that 10 or 20c is seriously possible then you would be on the options REGARDLESS of the rights issue value currently in RRS.
ST I think they are propbably valued about right now - as an option holder I really want the rights to ge ex so I am getting a true gain (not a diluted one) from any SP increase in RRS.
And for heaven sake would people PLEASE stop suggesting the company wants the options excercised !!! Every company in the world would like options exercised early but it is simply an ASX requirement that the company notify all option holders of their right to excercise and participate. If you can't do the math and realise it is stupid to excercise rather than sell the option and buy the fully paids you shouldn't be worrying about it.