I would be bummed out if I found a Christmas tree farm of BIG electrolytic caps on my board, but not as bummed as an irrepairable board due to capacitor acid leakage. I just posted the following elsewhere, but since this thread is a gathering of knowledge, I'll re-post here.

I'm thinking of going with aluminum organic polymers in the future. They're twice the price but have the stock look and my understanding is that they won't leak like an electrolytic will.

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Yeah, they do not have a fluid inside of them. They seem to get a good recommendation as a high reliability tantalum alternative from NASA:

A destructive test with massive current over stress to fail the polymer aluminum capacitors reveals that all polymer aluminum capacitors failed in a benign mode without ignition, combustion, or any other catastrophic failures.

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Apparently there are other polymer/aluminum constructions besides the aluminum can/wound structure as shown in the source doc. Here is another example:



Source: http://nepp.nasa.gov/files/20389/09_005_GSFC_Williams_Liu%20APC%20Final%20Report.pdf