You run into problems where someone else's code has opened and closed tables and leaves gaps in the workarea numbers used.
Provided the USE ... IN 0 form is always used, then there's no problem because the first unused workarea is reused. Either SELECT 0 then USE or USE...IN 0 opens in the lowest numbered unused workarea.

SELECT(1) returns the highest numbered unused workarea, which in VFP is a staggering 32767.
USE ... IN SELECT(1) will open a table in the highest unused workarea.
A following SELECT(1) returns 32766 because 32767 is in use.