Again, I agree that you don't want to disrupt the event. But again OP stated he discreetly went to the planner and asked about payment. The planner told him to go find Tony. This is pure planning. As I said had the wedding planner or wedding party just said we are starting X, please wait, I'm sure op would have been fine. The fact the planner said Tony has your money with no explanation would further cast doubt in my mind I was going to get paid. But I agree the best option is always a healthy diplomatic situation. (I'm not advocating disrupting the wedding or threatening violence)
As to the legal opinion I'm not criticizing I'm just stating fact. Yes, you want a contract to protect you, but the reality is in a normal wedding setting it would be cost/time prohibitive to sue to recover 1000-3000. Unless you have a lawyer on retainer. (Which I imagine is rare for a wedding band). That's after considerations like trying to find the correct address to serve the lawsuit or having a person who avoids the service of the lawsuit. Or for example, bridal party/person says they paid you cash. Now it's a he said they said situation with little evidence.
You're leaving out some important stuff. OP came here seeking advice because he feels he contributed to a disturbance and it's weighing on him. If everything was hunky dory and he had a clear conscience, I don't think he'd have done that. I've read a lot of his previous posts, he seems to run a tight entertainment business, has a lot of great advice to offer in that regard, so I'm not surprised he'd want to air this incident out and solicit opinions about what went wrong.
In the middle of the reception, apparently during the dinner hour, when the check couldn't be readily produced, the wedding party starts "scurrying around to scrape up cash" to pay OP. WTH??? Unbelievable. How embarrassing; I would have tried to crawl into my shoes. I've never seen or heard of anything quite like that before. That is totally unacceptable in my world. He also noticed that the meal was being delayed as a result. That's his concern, he derailed the flow of the event and contributed to a blatantly awkward situation, and I share that concern. This should never have gone any further than OP and the person responsible for paying him, but it did. The problem got to the bride and her wedding party, which is a big no-no, the very thing all vendors should avoid at all costs. Any indiscretion on OP's part that lead to that unfortunate result would be a big problem for me and my entertainment business and weigh on my conscience as well.
Ever been to small claims court? You don't need an attorney. It's a very simple and straight-forward process. The evidence is simple: Magistrate looks over the contract (which has a valid address for the couple as any smart business person would ensure). "Mr and Mrs. Jones, please produce for the court proof of payment in full." If they can't produce something tangible (and the "cash" thing won't pass muster in court, way too obvious and transparent), small claims court magistrate finds in favor of the plaintiff. I don't understand why you keep going on about excessive and exaggerated attorney fees; the necessity for such a thing is so remote it's a non-factor. And, from my perspective, the most important detail is in 15 years I've been paid late a few times but never had to exercise the legal option to enforce the contract and get paid in full. I think it would be an exceedingly rare incidence with the formal event client to have to go full enchilada and hire an attorney.
Bottom line: OP would have gotten paid, one way or another, today, tomorrow, or in a week, that is a virtual certainty. After he hit the first speed bump he should have laid off. He could have slipped the wedding planner a note and waited in his car. There are many ways this could have been avoided. Any part he played in the ensuing disruption was not worth the risk. I've seen brides and wedding party members get a bad taste in their mouths over far less, even if they are the ones that screwed up.
That saying about the customer always being right goes 100 fold for the smart wedding vendor.
You folks who don't do this for a living or very often, follow your gut. Be the limo driver who dumps the wedding couple off on the side of the road. Be the macho entertainer who refuses to play a note because you weren't paid in full on time. Ruin the most important day of this couple's lives, that's your prerogative.
But for those of us who depend on these clients for our livelihoods, or who take it that seriously, our intuitions warrant a much more realistic and tempered approach.
Sometimes the best laid plans go south. It's what you do next that defines you as a professional.