In blitz chess, does “touch is a move” apply?
That depends. The national scholastic guidelines suggest clock move rather than touch move. Based on some surveys done it has been reported that clock move is actually a little more common than touch move for blitz. Touch move would be the default for a USCF-rated tournament unless otherwise stated (and I’d think that it would be enough of a variance to require stating in the advance publicity).
main.uschess.org/images/stories/ … v.2007.pdf
It looks like touch move applies for USCF blitz rules.
Which is why it is the default. However. some USCF quick-rated blitz tournaments use clock-move (with prior announcements). The recent blitz tournaments at the scholastic nationals are included in that group (following the guidelines of the scholastic council).