Increased costs refer to the higher fees or expenses that users may face when using a trustless bridge with reduced liquidity. This can include:

1. Higher transaction fees: Users may pay more to process transactions, as liquidity providers demand higher fees to compensate for the increased risk.

2. Wider bid-ask spreads: The difference between the prices at which buyers and sellers are willing to trade can increase, resulting in higher costs for users.

3. Slippage: Users may experience larger price movements when executing trades, leading to higher costs and reduced profitability.

4. Premiums for liquidity: Users may pay a premium to access liquidity, especially during times of high market stress or volatility.

5. Increased borrowing costs: Users may face higher interest rates or fees when borrowing assets, as lenders demand higher returns to compensate for the increased risk.

These increased costs can make it more difficult for users to trade, borrow, or lend assets, reducing the overall usability and appeal of the trustless bridge. To mitigate these costs, trustless bridges can implement measures such as liquidity incentives, market making, and risk management tools to improve liquidity and reduce the burden on users.