Might be difficult for lesser altcoin which don't have good light wallet. Usually you're either forced to use crap or full node wallet.
Lesser known altcoins' blockchain is usually small enough, using a full node wallet should be not a problem.
The problem is the day traders / liquidity providers: they do keep bigger funds in order to grab some cents and this is quite a blow for them.
But the rest, i.e. normal miners should have not kept money there.