'"Follow you team's guidelines" is not applicable since we have none' - well, then have a meeting and decide how you want to do it (possibly including in what cases it is OK to deviate from that decision). If you have retros, you could bring it up there. There's no industry consensus on this, different teams follow different conventions. A lot of it might come down to personal taste. E.g., one thing to consider is what reads better for you:
if (areMultipleRowsSelected()) vs if (multipleRowsSelected()).