I booked flights leaving the UK very tightly soon after when I would receive my visa (see I thought I'd get my visa when I got my passport back, but no, ok, another up-to ten days of waiting

What are the chances I will have to show my BRP to immigration when I plan to LEAVE the uk next week?
I was hoping to risk it and have a friend post my BRP to me while I'm away, so I'd have it for my way back - but maybe that's too much of a risk and I will waste my time packing my bags and not delaying my flight while I still can - or maybe if I explain to them, they let me go through and say it's my own fault if I don't have my BRP on my way back????? Somehow I doubt that though, the guidelines state "You must take your permit with you if you go abroad while you have permission to stay in the UK".....they probably will ask to see it, the first time I leave UK with my new visa, right?
Thanks for your thoughts.