Oddity in 660_to_700 migration.
See this line:
http://code.vtiger.com/vtiger/vtigercrm/blob/master/modules/Migration/schema/660_to_700.php#L954
which sets the defaultvalue column to TEXT.
Well if you look at the manifest for the Webform module in pkg or packages it is still creating this table such that defaultvalue is set to VARCHAR(200).
So this line of code is either redundant or the module package needs updating I guess.