Despite what we teach children, there is in fact nothing magical about the words 'please', 'thank you', and 'you're welcome'. What's important is that the concepts behind those words get communicated.
Insisting on the specific words regardless of actual gratitude communicated would be just as misguided as insisting that one must be thanked on personal stationary, hand written and addressed, and that thanks offered through any other medium are insufficient.
In other words, it would be nitpicky and graceless.