I still clip and rip..I have never noticed my fabric "stretching", but if yours does then simply wash it and it will shrink back to were it needs to be, or if you are of the NO washing set, then spray it and iron and it will be fine...
I have one of the measuring machines and it works just fine!
I was also taught to PULL threads in sheers and always cut plaids and strips by opening up the fabric and cutting with scissors...if you buy a plaid now and it is cut with a rotary you can kiss 5" or more good bye when you try to straighten it out at home!
back in the day, tearing was a faster way of cutting, but it also showed the buyer the quality of the fabric! It always tore ON GRAIN so your fabric was easier to use!
Rotary cutting does not nothing to enhance the quality of your purchase!