table-detect-cell-alignment

table-detect-cell-alignment is a variable defined in `table.el'.
Its value is

t

Documentation:
Detect cell contents alignment automatically.
When non-nil cell alignment is automatically determined by the
appearance of the current cell contents when recognizing tables as a
whole. This applies to `table-recognize', `table-recognize-region'
and `table-recognize-table' but not to `table-recognize-cell'.

You can customize this variable.