Well its likely to stress the output devices - limit the current with a resistor - these days 2mA can be
very bright with high-efficiency LEDs. You must have adequate decoupling, I think this has been mentioned.
74HCxx seems to be cheaper than CD4000 series from where I buy chips. These jelly-bean parts should
be so cheap anyway that its not a factor! CD4000 will be end-of-lifed at some point I fear, they've
had a good run.