Sergey,
I don't have 2.x available to test. But
&~ will work equally well as an end of line comment in that version (as well as in VFP8) because of the way the parser works. Unless && is documented as an end-of-line comment marker explicitly in the help file it doesn't count.
>I belive that '&&' goes back to the dbase II. Anyway, I tested it in Fox 2.6a before posting and there's excerpt from FoxPro 2.6 help