The previous weekend a local sport shop in the mall sponsored a hunting expo in the parking lot. There was an assortment of tent sizes including 10X80, 20X20, 40X60 western style frames ballasted with 200lb concrete blocks. Please trust my judgment when I say that every tent installation was under ballasted by thousands of pounds.
I am not against using concrete blocks for ballasting as long as you have actually attempted to calculate the correct amount of ballasting for each tent and every leg that touches mother earth is ballasted with concrete blocks.
Unfortunately, a landlord may object to driving stakes into their parking lot. There is a valid reason for concern when generating and then not properly repairing holes created by driving stakes in the blacktop. Water seeps into the hole and will deteriorate the particles causing additional erosion and produces a larger hole. However, there is a fix for this and here is one of many solutions. http://www.homedepot.com/p/Quikrete-50-lb-Commercial-Grade-Blacktop-Repair-170152/100545936
There are two elements that influence every event and one is safety. For this event, in my estimation, the wind load rating was way below manufacturer specifications. You form your own opinion by viewing the photos and we can agree or respectfully disagree. The second element is the economic issue. Two companies bid on the project and one actually suggested staking or ballasting the job correctly and the other, refer to photo. The client will typically accept the lowest bid unless the client understands the ramification of hosting an event that is not a safe haven. Your presentation is a delicate balance between the value of safety, additional cost, losing the event to a competitor, the client changing the venue or canceling the event. If the client insists that you lower your proposal to match your competitor fire the client and enjoy your weekend.
And this brings us back to Proclaiming October as Blacktop Parking Lot Patching Month. The old adage that the customer is always right does not mean that the customer understands what is the appropriate solution for their event. Explain or if possible demonstrate an initiated solution that will repair the parking lot after the event is over. You have now merged both elements of safety and economics along with peace of mind for you and your client that this is a standard of reasonable expectation for their parking lot event.