Verified answer

mmm I am Argentinian and I never heard about that.

For ser, it is "TIEMPO" - as in, you use ser when it is:

Time (Monday, four o'clock)

Identification (he is Bob)

Event (such as a concert, party, or wedding)

Material (cotton, wood, metal, plastic)

Possession (his book, her shoes)

Origin (from Illinois, China, Paris)

For estar, it is "PLACE" - as in, you use ser when it is:

Position (on the table)

Location (the door is open)

Action (the book is falling)

Condition (he is sick)

Emotion (she is worried)

Hope this helps!