2 Hybrid question: plasmid stability

[ehrhardt at mpimg-berlin-dahlem.mpg.de]

I am having a question concerning plasmid stability in Yeast.
I am currently using a two hybrid system from Stratagene. They recommend
sequencial transformation with bait following bank vectors. After bait 
tranformation they recommend growing transformands in YPD-medium  
(non selective conditions). Is this really recommendable? How big are the
chances of spontanous plasmid loss lowering my cotransformation rate?

I would be grateful for hints.
Pleas mail:  EHRHARDT at mpimg-berlin-dahlem.mpg.de

Thanks a lot!